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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_preface');" title="Preface"> Preface </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#getting_started');" title="Getting Started"> Getting Started </a>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#configuration');" title="Apache HBase Configuration"> Apache HBase Configuration </a>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_configuration_files');" title="3. Configuration Files"> 3. Configuration Files </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#basic.prerequisites');" title="4. Basic Prerequisites"> 4. Basic Prerequisites </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#standalone_dist');" title="5. HBase run modes: Standalone and Distributed"> 5. HBase run modes: Standalone and Distributed </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#confirm');" title="6. Running and Confirming Your Installation"> 6. Running and Confirming Your Installation </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#config.files');" title="7. Default Configuration"> 7. Default Configuration </a> </li>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase.versioning');" title="11. HBase version number and compatibility"> 11. HBase version number and compatibility </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_rollback');" title="12. Rollback"> 12. Rollback </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_upgrade_paths');" title="13. Upgrade Paths"> 13. Upgrade Paths </a> </li>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#shell');" title="The Apache HBase Shell"> The Apache HBase Shell </a>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#scripting');" title="14. Scripting with Ruby"> 14. Scripting with Ruby </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_running_the_shell_in_non_interactive_mode');" title="15. Running the Shell in Non-Interactive Mode"> 15. Running the Shell in Non-Interactive Mode </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase.shell.noninteractive');" title="16. HBase Shell in OS Scripts"> 16. HBase Shell in OS Scripts </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_read_hbase_shell_commands_from_a_command_file');" title="17. Read HBase Shell Commands from a Command File"> 17. Read HBase Shell Commands from a Command File </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_passing_vm_options_to_the_shell');" title="18. Passing VM Options to the Shell"> 18. Passing VM Options to the Shell </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_overriding_configuration_starting_the_hbase_shell');" title="19. Overriding configuration starting the HBase Shell"> 19. Overriding configuration starting the HBase Shell </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_shell_tricks');" title="20. Shell Tricks"> 20. Shell Tricks </a> </li>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#datamodel');" title="Data Model"> Data Model </a>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#conceptual.view');" title="21. Conceptual View"> 21. Conceptual View </a> </li>
 <li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#physical.view');" title="22. Physical View"> 22. Physical View </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_namespace');" title="23. Namespace"> 23. Namespace </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_table');" title="24. Table"> 24. Table </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_row');" title="25. Row"> 25. Row </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#columnfamily');" title="26. Column Family"> 26. Column Family </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_cells');" title="27. Cells"> 27. Cells </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_data_model_operations');" title="28. Data Model Operations"> 28. Data Model Operations </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#versions');" title="29. Versions"> 29. Versions </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#dm.sort');" title="30. Sort Order"> 30. Sort Order </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#dm.column.metadata');" title="31. Column Metadata"> 31. Column Metadata </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#joins');" title="32. Joins"> 32. Joins </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_acid');" title="33. ACID"> 33. ACID </a> </li>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#schema');" title="HBase and Schema Design"> HBase and Schema Design </a>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#table_schema_rules_of_thumb');" title="35. Table Schema Rules Of Thumb"> 35. Table Schema Rules Of Thumb </a> </li>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#regionserver_sizing_rules_of_thumb');" title="RegionServer Sizing Rules of Thumb"> RegionServer Sizing Rules of Thumb </a>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#number.of.cfs');" title="36. On the number of column families"> 36. On the number of column families </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#rowkey.design');" title="37. Rowkey Design"> 37. Rowkey Design </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#schema.versions');" title="38. Number of Versions"> 38. Number of Versions </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#supported.datatypes');" title="39. Supported Datatypes"> 39. Supported Datatypes </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#schema.joins');" title="40. Joins"> 40. Joins </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#ttl');" title="41. Time To Live (TTL)"> 41. Time To Live (TTL) </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#cf.keep.deleted');" title="42. Keeping Deleted Cells"> 42. Keeping Deleted Cells </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#secondary.indexes');" title="43. Secondary Indexes and Alternate Query Paths"> 43. Secondary Indexes and Alternate Query Paths </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_constraints');" title="44. Constraints"> 44. Constraints </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#schema.casestudies');" title="45. Schema Design Case Studies"> 45. Schema Design Case Studies </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#schema.ops');" title="46. Operational and Performance Configuration Options"> 46. Operational and Performance Configuration Options </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_special_cases');" title="47. Special Cases"> 47. Special Cases </a> </li>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#mapreduce');" title="HBase and MapReduce"> HBase and MapReduce </a>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase.mapreduce.classpath');" title="48. HBase, MapReduce, and the CLASSPATH"> 48. HBase, MapReduce, and the CLASSPATH </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_mapreduce_scan_caching');" title="49. MapReduce Scan Caching"> 49. MapReduce Scan Caching </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_bundled_hbase_mapreduce_jobs');" title="50. Bundled HBase MapReduce Jobs"> 50. Bundled HBase MapReduce Jobs </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_hbase_as_a_mapreduce_job_data_source_and_data_sink');" title="51. HBase as a MapReduce Job Data Source and Data Sink"> 51. HBase as a MapReduce Job Data Source and Data Sink </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_writing_hfiles_directly_during_bulk_import');" title="52. Writing HFiles Directly During Bulk Import"> 52. Writing HFiles Directly During Bulk Import </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_rowcounter_example');" title="53. RowCounter Example"> 53. RowCounter Example </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#splitter');" title="54. Map-Task Splitting"> 54. Map-Task Splitting </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#mapreduce.example');" title="55. HBase MapReduce Examples"> 55. HBase MapReduce Examples </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#mapreduce.htable.access');" title="56. Accessing Other HBase Tables in a MapReduce Job"> 56. Accessing Other HBase Tables in a MapReduce Job </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#mapreduce.specex');" title="57. Speculative Execution"> 57. Speculative Execution </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#cascading');" title="58. Cascading"> 58. Cascading </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#security');" title="Securing Apache HBase"> Securing Apache HBase </a>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_web_ui_security');" title="59. Web UI Security"> 59. Web UI Security </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase.secure.configuration');" title="60. Secure Client Access to Apache HBase"> 60. Secure Client Access to Apache HBase </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase.secure.simpleconfiguration');" title="61. Simple User Access to Apache HBase"> 61. Simple User Access to Apache HBase </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_securing_access_to_hdfs_and_zookeeper');" title="62. Securing Access to HDFS and ZooKeeper"> 62. Securing Access to HDFS and ZooKeeper </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_securing_access_to_your_data');" title="63. Securing Access To Your Data"> 63. Securing Access To Your Data </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#security.example.config');" title="64. Security Configuration Example"> 64. Security Configuration Example </a> </li>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_architecture');" title="Architecture"> Architecture </a>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#arch.overview');" title="65. Overview"> 65. Overview </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#arch.catalog');" title="66. Catalog Tables"> 66. Catalog Tables </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#architecture.client');" title="67. Client"> 67. Client </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#client.filter');" title="68. Client Request Filters"> 68. Client Request Filters </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#architecture.master');" title="69. Master"> 69. Master </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#regionserver.arch');" title="70. RegionServer"> 70. RegionServer </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#regions.arch');" title="71. Regions"> 71. Regions </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#arch.bulk.load');" title="72. Bulk Loading"> 72. Bulk Loading </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#arch.hdfs');" title="73. HDFS"> 73. HDFS </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#arch.timelineconsistent.reads');" title="74. Timeline-consistent High Available Reads"> 74. Timeline-consistent High Available Reads </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase_mob');" title="75. Storing Medium-sized Objects (MOB)"> 75. Storing Medium-sized Objects (MOB) </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#inmemory_compaction');" title="In-memory Compaction"> In-memory Compaction </a>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#imc.overview');" title="76. Overview"> 76. Overview </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_enabling');" title="77. Enabling"> 77. Enabling </a> </li>
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<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#syncreplication');" title="Synchronous Replication"> Synchronous Replication </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_background');" title="78. Background"> 78. Background </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_design');" title="79. Design"> 79. Design </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_operation_and_maintenance');" title="80. Operation and maintenance"> 80. Operation and maintenance </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase_apis');" title="Apache HBase APIs"> Apache HBase APIs </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_examples');" title="81. Examples"> 81. Examples </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#external_apis');" title="Apache HBase External APIs"> Apache HBase External APIs </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_rest');" title="82. REST"> 82. REST </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_thrift');" title="83. Thrift"> 83. Thrift </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#c');" title="84. C/C++ Apache HBase Client"> 84. C/C++ Apache HBase Client </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#jdo');" title="85. Using Java Data Objects (JDO) with HBase"> 85. Using Java Data Objects (JDO) with HBase </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#scala');" title="86. Scala"> 86. Scala </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#jython');" title="87. Jython"> 87. Jython </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#thrift');" title="Thrift API and Filter Language"> Thrift API and Filter Language </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#thrift.filter_language');" title="88. Filter Language"> 88. Filter Language </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#cp');" title="Apache HBase Coprocessors"> Apache HBase Coprocessors </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_coprocessor_overview');" title="89. Coprocessor Overview"> 89. Coprocessor Overview </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_types_of_coprocessors');" title="90. Types of Coprocessors"> 90. Types of Coprocessors </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#cp_loading');" title="91. Loading Coprocessors"> 91. Loading Coprocessors </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#cp_example');" title="92. Examples"> 92. Examples </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_guidelines_for_deploying_a_coprocessor');" title="93. Guidelines For Deploying A Coprocessor"> 93. Guidelines For Deploying A Coprocessor </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_restricting_coprocessor_usage');" title="94. Restricting Coprocessor Usage"> 94. Restricting Coprocessor Usage </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#performance');" title="Apache HBase Performance Tuning"> Apache HBase Performance Tuning </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#perf.os');" title="95. Operating System"> 95. Operating System </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#perf.network');" title="96. Network"> 96. Network </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#jvm');" title="97. Java"> 97. Java </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#perf.configurations');" title="98. HBase Configurations"> 98. HBase Configurations </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#perf.zookeeper');" title="99. ZooKeeper"> 99. ZooKeeper </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#perf.schema');" title="100. Schema Design"> 100. Schema Design </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#perf.general');" title="101. HBase General Patterns"> 101. HBase General Patterns </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#perf.writing');" title="102. Writing to HBase"> 102. Writing to HBase </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#perf.reading');" title="103. Reading from HBase"> 103. Reading from HBase </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#perf.deleting');" title="104. Deleting from HBase"> 104. Deleting from HBase </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#perf.hdfs');" title="105. HDFS"> 105. HDFS </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#perf.ec2');" title="106. Amazon EC2"> 106. Amazon EC2 </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#perf.hbase.mr.cluster');" title="107. Collocating HBase and MapReduce"> 107. Collocating HBase and MapReduce </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#perf.casestudy');" title="108. Case Studies"> 108. Case Studies </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#profiler');" title="Profiler Servlet"> Profiler Servlet </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_background_2');" title="109. Background"> 109. Background </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_prerequisites_2');" title="110. Prerequisites"> 110. Prerequisites </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_usage');" title="111. Usage"> 111. Usage </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_ui');" title="112. UI"> 112. UI </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_notes');" title="113. Notes"> 113. Notes </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble');" title="Troubleshooting and Debugging Apache HBase"> Troubleshooting and Debugging Apache HBase </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.general');" title="114. General Guidelines"> 114. General Guidelines </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.log');" title="115. Logs"> 115. Logs </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.resources');" title="116. Resources"> 116. Resources </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.tools');" title="117. Tools"> 117. Tools </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.client');" title="118. Client"> 118. Client </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.mapreduce');" title="119. MapReduce"> 119. MapReduce </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.namenode');" title="120. NameNode"> 120. NameNode </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.network');" title="121. Network"> 121. Network </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.rs');" title="122. RegionServer"> 122. RegionServer </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.master');" title="123. Master"> 123. Master </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.zookeeper');" title="124. ZooKeeper"> 124. ZooKeeper </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.ec2');" title="125. Amazon EC2"> 125. Amazon EC2 </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.versions');" title="126. HBase and Hadoop version issues"> 126. HBase and Hadoop version issues </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_hbase_and_hdfs');" title="127. HBase and HDFS"> 127. HBase and HDFS </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.tests');" title="128. Running unit or integration tests"> 128. Running unit or integration tests </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.casestudy');" title="129. Case Studies"> 129. Case Studies </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#trouble.crypto');" title="130. Cryptographic Features"> 130. Cryptographic Features </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_operating_system_specific_issues');" title="131. Operating System Specific Issues"> 131. Operating System Specific Issues </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_jdk_issues');" title="132. JDK Issues"> 132. JDK Issues </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#casestudies');" title="Apache HBase Case Studies"> Apache HBase Case Studies </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#casestudies.overview');" title="133. Overview"> 133. Overview </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#casestudies.schema');" title="134. Schema Design"> 134. Schema Design </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#casestudies.perftroub');" title="135. Performance/Troubleshooting"> 135. Performance/Troubleshooting </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#ops_mgt');" title="Apache HBase Operational Management"> Apache HBase Operational Management </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#tools');" title="136. HBase Tools and Utilities"> 136. HBase Tools and Utilities </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#ops.regionmgt');" title="137. Region Management"> 137. Region Management </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#node.management');" title="138. Node Management"> 138. Node Management </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase_metrics');" title="139. HBase Metrics"> 139. HBase Metrics </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#ops.monitoring');" title="140. HBase Monitoring"> 140. HBase Monitoring </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_cluster_replication');" title="141. Cluster Replication"> 141. Cluster Replication </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_running_multiple_workloads_on_a_single_cluster');" title="142. Running Multiple Workloads On a Single Cluster"> 142. Running Multiple Workloads On a Single Cluster </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#ops.backup');" title="143. HBase Backup"> 143. HBase Backup </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#ops.snapshots');" title="144. HBase Snapshots"> 144. HBase Snapshots </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#snapshots_azure');" title="145. Storing Snapshots in Microsoft Azure Blob Storage"> 145. Storing Snapshots in Microsoft Azure Blob Storage </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#ops.capacity');" title="146. Capacity Planning and Region Sizing"> 146. Capacity Planning and Region Sizing </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#table.rename');" title="147. Table Rename"> 147. Table Rename </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#rsgroup');" title="148. RegionServer Grouping"> 148. RegionServer Grouping </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#normalizer');" title="149. Region Normalizer"> 149. Region Normalizer </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#developer');" title="Building and Developing Apache HBase"> Building and Developing Apache HBase </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#getting.involved');" title="150. Getting Involved"> 150. Getting Involved </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#repos');" title="151. Apache HBase Repositories"> 151. Apache HBase Repositories </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_ides');" title="152. IDEs"> 152. IDEs </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#build');" title="153. Building Apache HBase"> 153. Building Apache HBase </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#releasing');" title="154. Releasing Apache HBase"> 154. Releasing Apache HBase </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase.rc.voting');" title="155. Voting on Release Candidates"> 155. Voting on Release Candidates </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase.release.announcement');" title="156. Announcing Releases"> 156. Announcing Releases </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#documentation');" title="157. Generating the HBase Reference Guide"> 157. Generating the HBase Reference Guide </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase.org');" title="158. Updating"> 158. Updating </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase.tests');" title="159. Tests"> 159. Tests </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#developing');" title="160. Developer Guidelines"> 160. Developer Guidelines </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#unit.tests');" title="Unit Testing HBase Applications"> Unit Testing HBase Applications </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_junit');" title="161. JUnit"> 161. JUnit </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#mockito');" title="162. Mockito"> 162. Mockito </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_mrunit');" title="163. MRUnit"> 163. MRUnit </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_integration_testing_with_an_hbase_mini_cluster');" title="164. Integration Testing with an HBase Mini-Cluster"> 164. Integration Testing with an HBase Mini-Cluster </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#protobuf');" title="Protobuf in HBase"> Protobuf in HBase </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_protobuf');" title="165. Protobuf"> 165. Protobuf </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#pv2');" title="Procedure Framework (Pv2):"> Procedure Framework (Pv2): </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_procedures');" title="166. Procedures"> 166. Procedures </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_subprocedures');" title="167. Subprocedures"> 167. Subprocedures </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_procedureexecutor');" title="168. ProcedureExecutor"> 168. ProcedureExecutor </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_nonces');" title="169. Nonces"> 169. Nonces </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_wait_wake_suspend_yield');" title="170. Wait/Wake/Suspend/Yield"> 170. Wait/Wake/Suspend/Yield </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_locking');" title="171. Locking"> 171. Locking </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_procedure_types');" title="172. Procedure Types"> 172. Procedure Types </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_references');" title="173. References"> 173. References </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#amv2');" title="AMv2 Description for Devs"> AMv2 Description for Devs </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_background_3');" title="174. Background"> 174. Background </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_new_system');" title="175. New System"> 175. New System </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_procedures_detail');" title="176. Procedures Detail"> 176. Procedures Detail </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_ui_2');" title="177. UI"> 177. UI </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_logging');" title="178. Logging"> 178. Logging </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_implementation_notes');" title="179. Implementation Notes"> 179. Implementation Notes </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_new_configs');" title="180. New Configs"> 180. New Configs </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_tools');" title="181. Tools"> 181. Tools </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#zookeeper');" title="ZooKeeper"> ZooKeeper </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_using_existing_zookeeper_ensemble');" title="182. Using existing ZooKeeper ensemble"> 182. Using existing ZooKeeper ensemble </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#zk.sasl.auth');" title="183. SASL Authentication with ZooKeeper"> 183. SASL Authentication with ZooKeeper </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#community');" title="Community"> Community </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_decisions');" title="184. Decisions"> 184. Decisions </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#community.roles');" title="185. Community Roles"> 185. Community Roles </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase.commit.msg.format');" title="186. Commit Message format"> 186. Commit Message format </a> </li>
</ul> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_appendix');" title="Appendix"> Appendix </a>
<ul class="articles">
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#appendix_contributing_to_documentation');" title="Appendix A: Contributing to Documentation"> Appendix A: Contributing to Documentation </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#faq');" title="Appendix B: FAQ"> Appendix B: FAQ </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#appendix_acl_matrix');" title="Appendix C: Access Control Matrix"> Appendix C: Access Control Matrix </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#compression');" title="Appendix D: Compression and Data Block Encoding In HBase"> Appendix D: Compression and Data Block Encoding In HBase </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#sql');" title="Appendix E: SQL over HBase"> Appendix E: SQL over HBase </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#ycsb');" title="Appendix F: YCSB"> Appendix F: YCSB </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_hfile_format_2');" title="Appendix G: HFile format"> Appendix G: HFile format </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#other.info');" title="Appendix H: Other Information About HBase"> Appendix H: Other Information About HBase </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase.history');" title="Appendix I: HBase History"> Appendix I: HBase History </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#asf');" title="Appendix J: HBase and the Apache Software Foundation"> Appendix J: HBase and the Apache Software Foundation </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#orca');" title="Appendix K: Apache HBase Orca"> Appendix K: Apache HBase Orca </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#tracing');" title="Appendix L: Enabling Dapper-like Tracing in HBase"> Appendix L: Enabling Dapper-like Tracing in HBase </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#tracing.client.modifications');" title="187. Client Modifications"> 187. Client Modifications </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#tracing.client.shell');" title="188. Tracing from HBase Shell"> 188. Tracing from HBase Shell </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#hbase.rpc');" title="Appendix M: 0.95 RPC Specification"> Appendix M: 0.95 RPC Specification </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_known_incompatibilities_among_hbase_versions');" title="Appendix N: Known Incompatibilities Among HBase Versions"> Appendix N: Known Incompatibilities Among HBase Versions </a> </li>
<li class="chapter"> <a href="javascript:window.open('https://www.docs4dev.com/docs/en/apache-hbase/2.1/reference/book.html#_hbase_2_0_incompatible_changes');" title="189. HBase 2.0 Incompatible Changes"> 189. HBase 2.0 Incompatible Changes </a> </li>
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<h1>Apache HBase ™ Reference Guide</h1>
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<span id="author" class="author">Apache HBase Team</span>
<br>
<span id="email" class="email">&lt;<a href="email-protection.html#026a606371672f666774426e6b7176712c637263616a672c6d7065" target="_blank" rel="noopener noreferrer"><span class="__cf_email__" data-cfemail="b7dfd5d6c4d29ad3d2c1f7dbdec4c3c499d6c7d6d4dfd299d8c5d0">[email&#160;protected]</span> <i class="fa fa-external-link"></i></a>&gt;</span>
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<span id="revnumber">version 2.1.9</span>
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<div id="toc" class="toc2">
<div id="toctitle">
Contents
</div>
<ul class="sectlevel1">
<li><a href="#_preface">Preface</a></li>
<li><a href="#getting_started">Getting Started</a>
<ul class="sectlevel1">
<li><a href="#_introduction">1. Introduction</a></li>
<li><a href="#quickstart">2. Quick Start - Standalone HBase</a></li>
</ul> </li>
<li><a href="#configuration">Apache HBase Configuration</a>
<ul class="sectlevel1">
<li><a href="#_configuration_files">3. Configuration Files</a></li>
<li><a href="#basic.prerequisites">4. Basic Prerequisites</a></li>
<li><a href="#standalone_dist">5. HBase run modes: Standalone and Distributed</a></li>
<li><a href="#confirm">6. Running and Confirming Your Installation</a></li>
<li><a href="#config.files">7. Default Configuration</a></li>
<li><a href="#example_config">8. Example Configurations</a></li>
<li><a href="#important_configurations">9. The Important Configurations</a></li>
<li><a href="#dyn_config">10. Dynamic Configuration</a></li>
</ul> </li>
<li><a href="#upgrading">Upgrading</a>
<ul class="sectlevel1">
<li><a href="#hbase.versioning">11. HBase version number and compatibility</a></li>
<li><a href="#_rollback">12. Rollback</a></li>
<li><a href="#_upgrade_paths">13. Upgrade Paths</a></li>
</ul> </li>
<li><a href="#shell">The Apache HBase Shell</a>
<ul class="sectlevel1">
<li><a href="#scripting">14. Scripting with Ruby</a></li>
<li><a href="#_running_the_shell_in_non_interactive_mode">15. Running the Shell in Non-Interactive Mode</a></li>
<li><a href="#hbase.shell.noninteractive">16. HBase Shell in OS Scripts</a></li>
<li><a href="#_read_hbase_shell_commands_from_a_command_file">17. Read HBase Shell Commands from a Command File</a></li>
<li><a href="#_passing_vm_options_to_the_shell">18. Passing VM Options to the Shell</a></li>
<li><a href="#_overriding_configuration_starting_the_hbase_shell">19. Overriding configuration starting the HBase Shell</a></li>
<li><a href="#_shell_tricks">20. Shell Tricks</a></li>
</ul> </li>
<li><a href="#datamodel">Data Model</a>
<ul class="sectlevel1">
<li><a href="#conceptual.view">21. Conceptual View</a></li>
<li><a href="#physical.view">22. Physical View</a></li>
<li><a href="#_namespace">23. Namespace</a></li>
<li><a href="#_table">24. Table</a></li>
<li><a href="#_row">25. Row</a></li>
<li><a href="#columnfamily">26. Column Family</a></li>
<li><a href="#_cells">27. Cells</a></li>
<li><a href="#_data_model_operations">28. Data Model Operations</a></li>
<li><a href="#versions">29. Versions</a></li>
<li><a href="#dm.sort">30. Sort Order</a></li>
<li><a href="#dm.column.metadata">31. Column Metadata</a></li>
<li><a href="#joins">32. Joins</a></li>
<li><a href="#_acid">33. ACID</a></li>
</ul> </li>
<li><a href="#schema">HBase and Schema Design</a>
<ul class="sectlevel1">
<li><a href="#schema.creation">34. Schema Creation</a></li>
<li><a href="#table_schema_rules_of_thumb">35. Table Schema Rules Of Thumb</a></li>
</ul> </li>
<li><a href="#regionserver_sizing_rules_of_thumb">RegionServer Sizing Rules of Thumb</a>
<ul class="sectlevel1">
<li><a href="#number.of.cfs">36. On the number of column families</a></li>
<li><a href="#rowkey.design">37. Rowkey Design</a></li>
<li><a href="#schema.versions">38. Number of Versions</a></li>
<li><a href="#supported.datatypes">39. Supported Datatypes</a></li>
<li><a href="#schema.joins">40. Joins</a></li>
<li><a href="#ttl">41. Time To Live (TTL)</a></li>
<li><a href="#cf.keep.deleted">42. Keeping Deleted Cells</a></li>
<li><a href="#secondary.indexes">43. Secondary Indexes and Alternate Query Paths</a></li>
<li><a href="#_constraints">44. Constraints</a></li>
<li><a href="#schema.casestudies">45. Schema Design Case Studies</a></li>
<li><a href="#schema.ops">46. Operational and Performance Configuration Options</a></li>
<li><a href="#_special_cases">47. Special Cases</a></li>
</ul> </li>
<li><a href="#mapreduce">HBase and MapReduce</a>
<ul class="sectlevel1">
<li><a href="#hbase.mapreduce.classpath">48. HBase, MapReduce, and the CLASSPATH</a></li>
<li><a href="#_mapreduce_scan_caching">49. MapReduce Scan Caching</a></li>
<li><a href="#_bundled_hbase_mapreduce_jobs">50. Bundled HBase MapReduce Jobs</a></li>
<li><a href="#_hbase_as_a_mapreduce_job_data_source_and_data_sink">51. HBase as a MapReduce Job Data Source and Data Sink</a></li>
<li><a href="#_writing_hfiles_directly_during_bulk_import">52. Writing HFiles Directly During Bulk Import</a></li>
<li><a href="#_rowcounter_example">53. RowCounter Example</a></li>
<li><a href="#splitter">54. Map-Task Splitting</a></li>
<li><a href="#mapreduce.example">55. HBase MapReduce Examples</a></li>
<li><a href="#mapreduce.htable.access">56. Accessing Other HBase Tables in a MapReduce Job</a></li>
<li><a href="#mapreduce.specex">57. Speculative Execution</a></li>
<li><a href="#cascading">58. Cascading</a></li>
</ul> </li>
<li><a href="#security">Securing Apache HBase</a>
<ul class="sectlevel1">
<li><a href="#_web_ui_security">59. Web UI Security</a></li>
<li><a href="#hbase.secure.configuration">60. Secure Client Access to Apache HBase</a></li>
<li><a href="#hbase.secure.simpleconfiguration">61. Simple User Access to Apache HBase</a></li>
<li><a href="#_securing_access_to_hdfs_and_zookeeper">62. Securing Access to HDFS and ZooKeeper</a></li>
<li><a href="#_securing_access_to_your_data">63. Securing Access To Your Data</a></li>
<li><a href="#security.example.config">64. Security Configuration Example</a></li>
</ul> </li>
<li><a href="#_architecture">Architecture</a>
<ul class="sectlevel1">
<li><a href="#arch.overview">65. Overview</a></li>
<li><a href="#arch.catalog">66. Catalog Tables</a></li>
<li><a href="#architecture.client">67. Client</a></li>
<li><a href="#client.filter">68. Client Request Filters</a></li>
<li><a href="#architecture.master">69. Master</a></li>
<li><a href="#regionserver.arch">70. RegionServer</a></li>
<li><a href="#regions.arch">71. Regions</a></li>
<li><a href="#arch.bulk.load">72. Bulk Loading</a></li>
<li><a href="#arch.hdfs">73. HDFS</a></li>
<li><a href="#arch.timelineconsistent.reads">74. Timeline-consistent High Available Reads</a></li>
<li><a href="#hbase_mob">75. Storing Medium-sized Objects (MOB)</a></li>
</ul> </li>
<li><a href="#inmemory_compaction">In-memory Compaction</a>
<ul class="sectlevel1">
<li><a href="#imc.overview">76. Overview</a></li>
<li><a href="#_enabling">77. Enabling</a></li>
</ul> </li>
<li><a href="#syncreplication">Synchronous Replication</a>
<ul class="sectlevel1">
<li><a href="#_background">78. Background</a></li>
<li><a href="#_design">79. Design</a></li>
<li><a href="#_operation_and_maintenance">80. Operation and maintenance</a></li>
</ul> </li>
<li><a href="#hbase_apis">Apache HBase APIs</a>
<ul class="sectlevel1">
<li><a href="#_examples">81. Examples</a></li>
</ul> </li>
<li><a href="#external_apis">Apache HBase External APIs</a>
<ul class="sectlevel1">
<li><a href="#_rest">82. REST</a></li>
<li><a href="#_thrift">83. Thrift</a></li>
<li><a href="#c">84. C/C++ Apache HBase Client</a></li>
<li><a href="#jdo">85. Using Java Data Objects (JDO) with HBase</a></li>
<li><a href="#scala">86. Scala</a></li>
<li><a href="#jython">87. Jython</a></li>
</ul> </li>
<li><a href="#thrift">Thrift API and Filter Language</a>
<ul class="sectlevel1">
<li><a href="#thrift.filter_language">88. Filter Language</a></li>
</ul> </li>
<li><a href="#cp">Apache HBase Coprocessors</a>
<ul class="sectlevel1">
<li><a href="#_coprocessor_overview">89. Coprocessor Overview</a></li>
<li><a href="#_types_of_coprocessors">90. Types of Coprocessors</a></li>
<li><a href="#cp_loading">91. Loading Coprocessors</a></li>
<li><a href="#cp_example">92. Examples</a></li>
<li><a href="#_guidelines_for_deploying_a_coprocessor">93. Guidelines For Deploying A Coprocessor</a></li>
<li><a href="#_restricting_coprocessor_usage">94. Restricting Coprocessor Usage</a></li>
</ul> </li>
<li><a href="#performance">Apache HBase Performance Tuning</a>
<ul class="sectlevel1">
<li><a href="#perf.os">95. Operating System</a></li>
<li><a href="#perf.network">96. Network</a></li>
<li><a href="#jvm">97. Java</a></li>
<li><a href="#perf.configurations">98. HBase Configurations</a></li>
<li><a href="#perf.zookeeper">99. ZooKeeper</a></li>
<li><a href="#perf.schema">100. Schema Design</a></li>
<li><a href="#perf.general">101. HBase General Patterns</a></li>
<li><a href="#perf.writing">102. Writing to HBase</a></li>
<li><a href="#perf.reading">103. Reading from HBase</a></li>
<li><a href="#perf.deleting">104. Deleting from HBase</a></li>
<li><a href="#perf.hdfs">105. HDFS</a></li>
<li><a href="#perf.ec2">106. Amazon EC2</a></li>
<li><a href="#perf.hbase.mr.cluster">107. Collocating HBase and MapReduce</a></li>
<li><a href="#perf.casestudy">108. Case Studies</a></li>
</ul> </li>
<li><a href="#profiler">Profiler Servlet</a>
<ul class="sectlevel1">
<li><a href="#_background_2">109. Background</a></li>
<li><a href="#_prerequisites_2">110. Prerequisites</a></li>
<li><a href="#_usage">111. Usage</a></li>
<li><a href="#_ui">112. UI</a></li>
<li><a href="#_notes">113. Notes</a></li>
</ul> </li>
<li><a href="#trouble">Troubleshooting and Debugging Apache HBase</a>
<ul class="sectlevel1">
<li><a href="#trouble.general">114. General Guidelines</a></li>
<li><a href="#trouble.log">115. Logs</a></li>
<li><a href="#trouble.resources">116. Resources</a></li>
<li><a href="#trouble.tools">117. Tools</a></li>
<li><a href="#trouble.client">118. Client</a></li>
<li><a href="#trouble.mapreduce">119. MapReduce</a></li>
<li><a href="#trouble.namenode">120. NameNode</a></li>
<li><a href="#trouble.network">121. Network</a></li>
<li><a href="#trouble.rs">122. RegionServer</a></li>
<li><a href="#trouble.master">123. Master</a></li>
<li><a href="#trouble.zookeeper">124. ZooKeeper</a></li>
<li><a href="#trouble.ec2">125. Amazon EC2</a></li>
<li><a href="#trouble.versions">126. HBase and Hadoop version issues</a></li>
<li><a href="#_hbase_and_hdfs">127. HBase and HDFS</a></li>
<li><a href="#trouble.tests">128. Running unit or integration tests</a></li>
<li><a href="#trouble.casestudy">129. Case Studies</a></li>
<li><a href="#trouble.crypto">130. Cryptographic Features</a></li>
<li><a href="#_operating_system_specific_issues">131. Operating System Specific Issues</a></li>
<li><a href="#_jdk_issues">132. JDK Issues</a></li>
</ul> </li>
<li><a href="#casestudies">Apache HBase Case Studies</a>
<ul class="sectlevel1">
<li><a href="#casestudies.overview">133. Overview</a></li>
<li><a href="#casestudies.schema">134. Schema Design</a></li>
<li><a href="#casestudies.perftroub">135. Performance/Troubleshooting</a></li>
</ul> </li>
<li><a href="#ops_mgt">Apache HBase Operational Management</a>
<ul class="sectlevel1">
<li><a href="#tools">136. HBase Tools and Utilities</a></li>
<li><a href="#ops.regionmgt">137. Region Management</a></li>
<li><a href="#node.management">138. Node Management</a></li>
<li><a href="#hbase_metrics">139. HBase Metrics</a></li>
<li><a href="#ops.monitoring">140. HBase Monitoring</a></li>
<li><a href="#_cluster_replication">141. Cluster Replication</a></li>
<li><a href="#_running_multiple_workloads_on_a_single_cluster">142. Running Multiple Workloads On a Single Cluster</a></li>
<li><a href="#ops.backup">143. HBase Backup</a></li>
<li><a href="#ops.snapshots">144. HBase Snapshots</a></li>
<li><a href="#snapshots_azure">145. Storing Snapshots in Microsoft Azure Blob Storage</a></li>
<li><a href="#ops.capacity">146. Capacity Planning and Region Sizing</a></li>
<li><a href="#table.rename">147. Table Rename</a></li>
<li><a href="#rsgroup">148. RegionServer Grouping</a></li>
<li><a href="#normalizer">149. Region Normalizer</a></li>
</ul> </li>
<li><a href="#developer">Building and Developing Apache HBase</a>
<ul class="sectlevel1">
<li><a href="#getting.involved">150. Getting Involved</a></li>
<li><a href="#repos">151. Apache HBase Repositories</a></li>
<li><a href="#_ides">152. IDEs</a></li>
<li><a href="#build">153. Building Apache HBase</a></li>
<li><a href="#releasing">154. Releasing Apache HBase</a></li>
<li><a href="#hbase.rc.voting">155. Voting on Release Candidates</a></li>
<li><a href="#hbase.release.announcement">156. Announcing Releases</a></li>
<li><a href="#documentation">157. Generating the HBase Reference Guide</a></li>
<li><a href="#hbase.org">158. Updating </a><a href="javascript:window.open('https://hbase.apache.org/');" target="_blank" rel="noopener noreferrer">hbase.apache.org <i class="fa fa-external-link"></i></a></li>
<li><a href="#hbase.tests">159. Tests</a></li>
<li><a href="#developing">160. Developer Guidelines</a></li>
</ul> </li>
<li><a href="#unit.tests">Unit Testing HBase Applications</a>
<ul class="sectlevel1">
<li><a href="#_junit">161. JUnit</a></li>
<li><a href="#mockito">162. Mockito</a></li>
<li><a href="#_mrunit">163. MRUnit</a></li>
<li><a href="#_integration_testing_with_an_hbase_mini_cluster">164. Integration Testing with an HBase Mini-Cluster</a></li>
</ul> </li>
<li><a href="#protobuf">Protobuf in HBase</a>
<ul class="sectlevel1">
<li><a href="#_protobuf">165. Protobuf</a></li>
</ul> </li>
<li><a href="#pv2">Procedure Framework (Pv2): </a><a href="javascript:window.open('https://issues.apache.org/jira/browse/HBASE-12439');" target="_blank" rel="noopener noreferrer">HBASE-12439 <i class="fa fa-external-link"></i></a>
<ul class="sectlevel1">
<li><a href="#_procedures">166. Procedures</a></li>
<li><a href="#_subprocedures">167. Subprocedures</a></li>
<li><a href="#_procedureexecutor">168. ProcedureExecutor</a></li>
<li><a href="#_nonces">169. Nonces</a></li>
<li><a href="#_wait_wake_suspend_yield">170. Wait/Wake/Suspend/Yield</a></li>
<li><a href="#_locking">171. Locking</a></li>
<li><a href="#_procedure_types">172. Procedure Types</a></li>
<li><a href="#_references">173. References</a></li>
</ul> </li>
<li><a href="#amv2">AMv2 Description for Devs</a>
<ul class="sectlevel1">
<li><a href="#_background_3">174. Background</a></li>
<li><a href="#_new_system">175. New System</a></li>
<li><a href="#_procedures_detail">176. Procedures Detail</a></li>
<li><a href="#_ui_2">177. UI</a></li>
<li><a href="#_logging">178. Logging</a></li>
<li><a href="#_implementation_notes">179. Implementation Notes</a></li>
<li><a href="#_new_configs">180. New Configs</a></li>
<li><a href="#_tools">181. Tools</a></li>
</ul> </li>
<li><a href="#zookeeper">ZooKeeper</a>
<ul class="sectlevel1">
<li><a href="#_using_existing_zookeeper_ensemble">182. Using existing ZooKeeper ensemble</a></li>
<li><a href="#zk.sasl.auth">183. SASL Authentication with ZooKeeper</a></li>
</ul> </li>
<li><a href="#community">Community</a>
<ul class="sectlevel1">
<li><a href="#_decisions">184. Decisions</a></li>
<li><a href="#community.roles">185. Community Roles</a></li>
<li><a href="#hbase.commit.msg.format">186. Commit Message format</a></li>
</ul> </li>
<li><a href="#_appendix">Appendix</a>
<ul class="sectlevel1">
<li><a href="#appendix_contributing_to_documentation">Appendix A: Contributing to Documentation</a></li>
<li><a href="#faq">Appendix B: FAQ</a></li>
<li><a href="#appendix_acl_matrix">Appendix C: Access Control Matrix</a></li>
<li><a href="#compression">Appendix D: Compression and Data Block Encoding In HBase</a></li>
<li><a href="#sql">Appendix E: SQL over HBase</a></li>
<li><a href="#ycsb">Appendix F: YCSB</a></li>
<li><a href="#_hfile_format_2">Appendix G: HFile format</a></li>
<li><a href="#other.info">Appendix H: Other Information About HBase</a></li>
<li><a href="#hbase.history">Appendix I: HBase History</a></li>
<li><a href="#asf">Appendix J: HBase and the Apache Software Foundation</a></li>
<li><a href="#orca">Appendix K: Apache HBase Orca</a></li>
<li><a href="#tracing">Appendix L: Enabling Dapper-like Tracing in HBase</a></li>
<li><a href="#tracing.client.modifications">187. Client Modifications</a></li>
<li><a href="#tracing.client.shell">188. Tracing from HBase Shell</a></li>
<li><a href="#hbase.rpc">Appendix M: 0.95 RPC Specification</a></li>
<li><a href="#_known_incompatibilities_among_hbase_versions">Appendix N: Known Incompatibilities Among HBase Versions</a></li>
<li><a href="#_hbase_2_0_incompatible_changes">189. HBase 2.0 Incompatible Changes</a></li>
</ul> </li>
</ul>
</div>
</div>
<div id="content">
<div id="preamble">
<div class="sectionbody">
<div>
<a href="javascript:window.open('https://hbase.apache.org/');" target="_blank" rel="noopener noreferrer"><img src="static/picture/hbase_logo_with_orca.png" alt="Apache HBase Logo"> <i class="fa fa-external-link"></i></a>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_preface"><a class="anchor" href="#_preface"></a>Preface</h2>
<div class="sectionbody">
<div class="paragraph">
<p>This is the official reference guide for the <a href="javascript:window.open('https://hbase.apache.org/');" target="_blank" rel="noopener noreferrer">HBase <i class="fa fa-external-link"></i></a> version it ships with.</p>
</div>
<div class="paragraph">
<p>Herein you will find either the definitive documentation on an HBase topic as of its standing when the referenced HBase version shipped, or it will point to the location in <a href="javascript:window.open('https://hbase.apache.org/apidocs/index.html');" target="_blank" rel="noopener noreferrer">Javadoc <i class="fa fa-external-link"></i></a> or <a href="javascript:window.open('https://issues.apache.org/jira/browse/HBASE');" target="_blank" rel="noopener noreferrer">JIRA <i class="fa fa-external-link"></i></a> where the pertinent information can be found.</p>
</div>
<div class="paragraph">
<div class="title">
About This Guide
</div>
<p>This reference guide is a work in progress. The source for this guide can be found in the _src/main/asciidoc directory of the HBase source. This reference guide is marked up using <a href="javascript:window.open('http://asciidoc.org/');" target="_blank" rel="noopener noreferrer">AsciiDoc <i class="fa fa-external-link"></i></a> from which the finished guide is generated as part of the 'site' build target. Run</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight notranslate"><code data-lang="bourne">mvn site</code></pre>
</div>
</div>
<div class="paragraph">
<p>to generate this documentation. Amendments and improvements to the documentation are welcomed. Click <a href="javascript:window.open('https://issues.apache.org/jira/secure/CreateIssueDetails!init.jspa?pid=12310753&amp;issuetype=1&amp;components=12312132&amp;summary=SHORT+DESCRIPTION');" target="_blank" rel="noopener noreferrer">this link <i class="fa fa-external-link"></i></a> to file a new documentation bug against Apache HBase with some values pre-selected.</p>
</div>
<div class="paragraph">
<div class="title">
Contributing to the Documentation
</div>
<p>For an overview of AsciiDoc and suggestions to get started contributing to the documentation, see the <a href="#appendix_contributing_to_documentation">relevant section later in this documentation</a>.</p>
</div>
<div class="paragraph">
<div class="title">
Heads-up if this is your first foray into the world of distributed computing…
</div>
<p>If this is your first foray into the wonderful world of Distributed Computing, then you are in for some interesting times. First off, distributed systems are hard; making a distributed system hum requires a disparate skillset that spans systems (hardware and software) and networking.</p>
</div>
<div class="paragraph">
<p>Your cluster’s operation can hiccup because of any of a myriad set of reasons from bugs in HBase itself through misconfigurations — misconfiguration of HBase but also operating system misconfigurations — through to hardware problems whether it be a bug in your network card drivers or an underprovisioned RAM bus (to mention two recent examples of hardware issues that manifested as "HBase is slow"). You will also need to do a recalibration if up to this your computing has been bound to a single box. Here is one good starting point: <a href="javascript:window.open('https://en.wikipedia.org/wiki/Fallacies_of_Distributed_Computing');" target="_blank" rel="noopener noreferrer">Fallacies of Distributed Computing <i class="fa fa-external-link"></i></a>.</p>
</div>
<div class="paragraph">
<p>That said, you are welcome.<br> It’s a fun place to be.<br> Yours, the HBase Community.</p>
</div>
<div class="paragraph">
<div class="title">
Reporting Bugs
</div>
<p>Please use <a href="javascript:window.open('https://issues.apache.org/jira/browse/hbase');" target="_blank" rel="noopener noreferrer">JIRA <i class="fa fa-external-link"></i></a> to report non-security-related bugs.</p>
</div>
<div class="paragraph">
<p>To protect existing HBase installations from new vulnerabilities, please <strong>do not</strong> use JIRA to report security-related bugs. Instead, send your report to the mailing list <a href="email-protection.html#94e4e6fde2f5e0f1d4fcf6f5e7f1baf5e4f5f7fcf1bafbe6f3" target="_blank" rel="noopener noreferrer"><span class="__cf_email__" data-cfemail="31414358475045547159535042541f5041505259541f5e4356">[email&#160;protected]</span> <i class="fa fa-external-link"></i></a>, which allows anyone to send messages, but restricts who can read them. Someone on that list will contact you to follow up on your report.</p>
</div>
<div id="hbase_supported_tested_definitions" class="paragraph">
<div class="title">
Support and Testing Expectations
</div>
<p>The phrases /supported/, /not supported/, /tested/, and /not tested/ occur several places throughout this guide. In the interest of clarity, here is a brief explanation of what is generally meant by these phrases, in the context of HBase.</p>
</div>
<div class="admonitionblock note">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-note" title="Note"></i> </td>
<td class="content"> Commercial technical support for Apache HBase is provided by many Hadoop vendors. This is not the sense in which the term /support/ is used in the context of the Apache HBase project. The Apache HBase team assumes no responsibility for your HBase clusters, your configuration, or your data. </td>
</tr>
</tbody>
</table>
</div>
<div class="dlist">
<dl>
<dt class="hdlist1">
Supported
</dt>
<dd>
<p>In the context of Apache HBase, /supported/ means that HBase is designed to work in the way described, and deviation from the defined behavior or functionality should be reported as a bug.</p>
</dd>
<dt class="hdlist1">
Not Supported
</dt>
<dd>
<p>In the context of Apache HBase, /not supported/ means that a use case or use pattern is not expected to work and should be considered an antipattern. If you think this designation should be reconsidered for a given feature or use pattern, file a JIRA or start a discussion on one of the mailing lists.</p>
</dd>
<dt class="hdlist1">
Tested
</dt>
<dd>
<p>In the context of Apache HBase, /tested/ means that a feature is covered by unit or integration tests, and has been proven to work as expected.</p>
</dd>
<dt class="hdlist1">
Not Tested
</dt>
<dd>
<p>In the context of Apache HBase, /not tested/ means that a feature or use pattern may or may not work in a given way, and may or may not corrupt your data or cause operational issues. It is an unknown, and there are no guarantees. If you can provide proof that a feature designated as /not tested/ does work in a given way, please submit the tests and/or the metrics so that other users can gain certainty about such features or use patterns.</p>
</dd>
</dl>
</div>
</div>
</div>
<h2 id="getting_started" class="sect0"><a class="anchor" href="#getting_started"></a>Getting Started</h2>
<div class="sect1">
<h2 id="_introduction"><a class="anchor" href="#_introduction"></a>1. Introduction</h2>
<div class="sectionbody">
<div class="paragraph">
<p><a href="#quickstart">Quickstart</a> will get you up and running on a single-node, standalone instance of HBase.</p>
</div>
</div>
</div>
<div class="sect1">
<h2 id="quickstart"><a class="anchor" href="#quickstart"></a>2. Quick Start - Standalone HBase</h2>
<div class="sectionbody">
<div class="paragraph">
<p>This section describes the setup of a single-node standalone HBase. A <em>standalone</em> instance has all HBase daemons — the Master, RegionServers, and ZooKeeper — running in a single JVM persisting to the local filesystem. It is our most basic deploy profile. We will show you how to create a table in HBase using the <code class="notranslate">hbase shell</code> CLI, insert rows into the table, perform put and scan operations against the table, enable or disable the table, and start and stop HBase.</p>
</div>
<div class="paragraph">
<p>Apart from downloading HBase, this procedure should take less than 10 minutes.</p>
</div>
<div class="sect2">
<h3 id="_jdk_version_requirements"><a class="anchor" href="#_jdk_version_requirements"></a>2.1. JDK Version Requirements</h3>
<div class="paragraph">
<p>HBase requires that a JDK be installed. See <a href="#java">Java</a> for information about supported JDK versions.</p>
</div>
</div>
<div class="sect2">
<h3 id="_get_started_with_hbase"><a class="anchor" href="#_get_started_with_hbase"></a>2.2. Get Started with HBase</h3>
<div class="olist arabic">
<div class="title">
Procedure: Download, Configure, and Start HBase in Standalone Mode
</div>
<ol class="arabic">
<li> <p>Choose a download site from this list of <a href="javascript:window.open('https://www.apache.org/dyn/closer.lua/hbase/');" target="_blank" rel="noopener noreferrer">Apache Download Mirrors <i class="fa fa-external-link"></i></a>. Click on the suggested top link. This will take you to a mirror of <em>HBase Releases</em>. Click on the folder named <em>stable</em> and then download the binary file that ends in <em>.tar.gz</em> to your local filesystem. Do not download the file ending in <em>src.tar.gz</em> for now.</p> </li>
<li> <p>Extract the downloaded file, and change to the newly-created directory.</p>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight notranslate"><code data-lang="java">$ tar xzvf hbase-2.1.9-bin.tar.gz
$ cd hbase-2.1.9/</code></pre>
</div>
</div> </li>
<li> <p>You are required to set the <code class="notranslate">JAVA_HOME</code> environment variable before starting HBase. You can set the variable via your operating system’s usual mechanism, but HBase provides a central mechanism, <em>conf/hbase-env.sh</em>. Edit this file, uncomment the line starting with <code class="notranslate">JAVA_HOME</code>, and set it to the appropriate location for your operating system. The <code class="notranslate">JAVA_HOME</code> variable should be set to a directory which contains the executable file <em>bin/java</em>. Most modern Linux operating systems provide a mechanism, such as /usr/bin/alternatives on RHEL or CentOS, for transparently switching between versions of executables such as Java. In this case, you can set <code class="notranslate">JAVA_HOME</code> to the directory containing the symbolic link to <em>bin/java</em>, which is usually <em>/usr</em>.</p>
<div class="listingblock">
<div class="content">
<pre class="notranslate">JAVA_HOME=/usr</pre>
</div>
</div> </li>
<li> <p>Edit <em>conf/hbase-site.xml</em>, which is the main HBase configuration file. At this time, you need to specify the directory on the local filesystem where HBase and ZooKeeper write data and acknowledge some risks. By default, a new directory is created under /tmp. Many servers are configured to delete the contents of <em>/tmp</em> upon reboot, so you should store the data elsewhere. The following configuration will store HBase’s data in the <em>hbase</em> directory, in the home directory of the user called <code class="notranslate">testuser</code>. Paste the <code class="notranslate">&lt;property&gt;</code> tags beneath the <code class="notranslate">&lt;configuration&gt;</code> tags, which should be empty in a new HBase install.</p>
<div class="exampleblock">
<div class="title">
Example 1. Example
<em>hbase-site.xml</em> for Standalone HBase
</div>
<div class="content">
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight notranslate"><code data-lang="xml"><span class="tag">&lt;configuration&gt;</span>
  <span class="tag">&lt;property&gt;</span>
    <span class="tag">&lt;name&gt;</span>hbase.rootdir<span class="tag">&lt;/name&gt;</span>
    <span class="tag">&lt;value&gt;</span>file:///home/testuser/hbase<span class="tag">&lt;/value&gt;</span>
  <span class="tag">&lt;/property&gt;</span>
  <span class="tag">&lt;property&gt;</span>
    <span class="tag">&lt;name&gt;</span>hbase.zookeeper.property.dataDir<span class="tag">&lt;/name&gt;</span>
    <span class="tag">&lt;value&gt;</span>/home/testuser/zookeeper<span class="tag">&lt;/value&gt;</span>
  <span class="tag">&lt;/property&gt;</span>
  <span class="tag">&lt;property&gt;</span>
    <span class="tag">&lt;name&gt;</span>hbase.unsafe.stream.capability.enforce<span class="tag">&lt;/name&gt;</span>
    <span class="tag">&lt;value&gt;</span>false<span class="tag">&lt;/value&gt;</span>
    <span class="tag">&lt;description&gt;</span>
      Controls whether HBase will check for stream capabilities (hflush/hsync).

      Disable this if you intend to run on LocalFileSystem, denoted by a rootdir
      with the 'file://' scheme, but be mindful of the NOTE below.

      WARNING: Setting this to false blinds you to potential data loss and
      inconsistent system state in the event of process and/or node failures. If
      HBase is complaining of an inability to use hsync or hflush it's most
      likely not a false positive.
    <span class="tag">&lt;/description&gt;</span>
  <span class="tag">&lt;/property&gt;</span>
<span class="tag">&lt;/configuration&gt;</span></code></pre>
</div>
</div>
</div>
</div>
<div class="paragraph">
<p>You do not need to create the HBase data directory. HBase will do this for you. If you create the directory, HBase will attempt to do a migration, which is not what you want.</p>
</div>
<div class="admonitionblock note">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-note" title="Note"></i> </td>
<td class="content"> The <em>hbase.rootdir</em> in the above example points to a directory in the <em>local filesystem</em>. The 'file://' prefix is how we denote local filesystem. You should take the WARNING present in the configuration example to heart. In standalone mode HBase makes use of the local filesystem abstraction from the Apache Hadoop project. That abstraction doesn’t provide the durability promises that HBase needs to operate safely. This is fine for local development and testing use cases where the cost of cluster failure is well contained. It is not appropriate for production deployments; eventually you will lose data. </td>
</tr>
</tbody>
</table>
</div> </li>
</ol>
</div>
<div class="paragraph">
<p>To home HBase on an existing instance of HDFS, set the <em>hbase.rootdir</em> to point at a directory up on your instance: e.g. <em>hdfs://namenode.example.org:8020/hbase</em>. For more on this variant, see the section below on Standalone HBase over HDFS.</p>
</div>
<div class="olist arabic">
<ol class="arabic">
<li> <p>The <em>bin/start-hbase.sh</em> script is provided as a convenient way to start HBase. Issue the command, and if all goes well, a message is logged to standard output showing that HBase started successfully. You can use the <code class="notranslate">jps</code> command to verify that you have one running process called <code class="notranslate">HMaster</code>. In standalone mode HBase runs all daemons within this single JVM, i.e. the HMaster, a single HRegionServer, and the ZooKeeper daemon. Go to <em><a href="javascript:window.open('http://localhost:16010/');" class="bare" target="_blank" rel="noopener noreferrer">http://localhost:16010 <i class="fa fa-external-link"></i></a></em> to view the HBase Web UI.</p>
<div class="admonitionblock note">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-note" title="Note"></i> </td>
<td class="content"> Java needs to be installed and available. If you get an error indicating that Java is not installed, but it is on your system, perhaps in a non-standard location, edit the <em>conf/hbase-env.sh</em> file and modify the <code class="notranslate">JAVA_HOME</code> setting to point to the directory that contains <em>bin/java</em> on your system. </td>
</tr>
</tbody>
</table>
</div> </li>
</ol>
</div>
<div id="shell_exercises" class="olist arabic">
<div class="title">
Procedure: Use HBase For the First Time
</div>
<ol class="arabic">
<li> <p>Connect to HBase.</p>
<div class="paragraph">
<p>Connect to your running instance of HBase using the <code class="notranslate">hbase shell</code> command, located in the <em class="path">bin/</em> directory of your HBase install. In this example, some usage and version information that is printed when you start HBase Shell has been omitted. The HBase Shell prompt ends with a <code class="notranslate">&gt;</code> character.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">$ ./bin/hbase shell
hbase(main):001:0&gt;</pre>
</div>
</div> </li>
<li> <p>Display HBase Shell Help Text.</p>
<div class="paragraph">
<p>Type <code class="notranslate">help</code> and press Enter, to display some basic usage information for HBase Shell, as well as several example commands. Notice that table names, rows, columns all must be enclosed in quote characters.</p>
</div> </li>
<li> <p>Create a table.</p>
<div class="paragraph">
<p>Use the <code class="notranslate">create</code> command to create a new table. You must specify the table name and the ColumnFamily name.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">hbase(main):001:0&gt; create 'test', 'cf'
0 row(s) in 0.4170 seconds

=&gt; Hbase::Table - test</pre>
</div>
</div> </li>
<li> <p>List Information About your Table</p>
<div class="paragraph">
<p>Use the <code class="notranslate">list</code> command to confirm your table exists</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">hbase(main):002:0&gt; list 'test'
TABLE
test
1 row(s) in 0.0180 seconds

=&gt; ["test"]</pre>
</div>
</div>
<div class="paragraph">
<p>Now use the <code class="notranslate">describe</code> command to see details, including configuration defaults</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">hbase(main):003:0&gt; describe 'test'
Table test is ENABLED
test
COLUMN FAMILIES DESCRIPTION
{NAME =&gt; 'cf', VERSIONS =&gt; '1', EVICT_BLOCKS_ON_CLOSE =&gt; 'false', NEW_VERSION_BEHAVIOR =&gt; 'false', KEEP_DELETED_CELLS =&gt; 'FALSE', CACHE_DATA_ON_WRITE =&gt;
'false', DATA_BLOCK_ENCODING =&gt; 'NONE', TTL =&gt; 'FOREVER', MIN_VERSIONS =&gt; '0', REPLICATION_SCOPE =&gt; '0', BLOOMFILTER =&gt; 'ROW', CACHE_INDEX_ON_WRITE =&gt; 'f
alse', IN_MEMORY =&gt; 'false', CACHE_BLOOMS_ON_WRITE =&gt; 'false', PREFETCH_BLOCKS_ON_OPEN =&gt; 'false', COMPRESSION =&gt; 'NONE', BLOCKCACHE =&gt; 'true', BLOCKSIZE
 =&gt; '65536'}
1 row(s)
Took 0.9998 seconds</pre>
</div>
</div> </li>
<li> <p>Put data into your table.</p>
<div class="paragraph">
<p>To put data into your table, use the <code class="notranslate">put</code> command.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">hbase(main):003:0&gt; put 'test', 'row1', 'cf:a', 'value1'
0 row(s) in 0.0850 seconds

hbase(main):004:0&gt; put 'test', 'row2', 'cf:b', 'value2'
0 row(s) in 0.0110 seconds

hbase(main):005:0&gt; put 'test', 'row3', 'cf:c', 'value3'
0 row(s) in 0.0100 seconds</pre>
</div>
</div>
<div class="paragraph">
<p>Here, we insert three values, one at a time. The first insert is at <code class="notranslate">row1</code>, column <code class="notranslate">cf:a</code>, with a value of <code class="notranslate">value1</code>. Columns in HBase are comprised of a column family prefix, <code class="notranslate">cf</code> in this example, followed by a colon and then a column qualifier suffix, <code class="notranslate">a</code> in this case.</p>
</div> </li>
<li> <p>Scan the table for all data at once.</p>
<div class="paragraph">
<p>One of the ways to get data from HBase is to scan. Use the <code class="notranslate">scan</code> command to scan the table for data. You can limit your scan, but for now, all data is fetched.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">hbase(main):006:0&gt; scan 'test'
ROW                                      COLUMN+CELL
 row1                                    column=cf:a, timestamp=1421762485768, value=value1
 row2                                    column=cf:b, timestamp=1421762491785, value=value2
 row3                                    column=cf:c, timestamp=1421762496210, value=value3
3 row(s) in 0.0230 seconds</pre>
</div>
</div> </li>
<li> <p>Get a single row of data.</p>
<div class="paragraph">
<p>To get a single row of data at a time, use the <code class="notranslate">get</code> command.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">hbase(main):007:0&gt; get 'test', 'row1'
COLUMN                                   CELL
 cf:a                                    timestamp=1421762485768, value=value1
1 row(s) in 0.0350 seconds</pre>
</div>
</div> </li>
<li> <p>Disable a table.</p>
<div class="paragraph">
<p>If you want to delete a table or change its settings, as well as in some other situations, you need to disable the table first, using the <code class="notranslate">disable</code> command. You can re-enable it using the <code class="notranslate">enable</code> command.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">hbase(main):008:0&gt; disable 'test'
0 row(s) in 1.1820 seconds

hbase(main):009:0&gt; enable 'test'
0 row(s) in 0.1770 seconds</pre>
</div>
</div>
<div class="paragraph">
<p>Disable the table again if you tested the <code class="notranslate">enable</code> command above:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">hbase(main):010:0&gt; disable 'test'
0 row(s) in 1.1820 seconds</pre>
</div>
</div> </li>
<li> <p>Drop the table.</p>
<div class="paragraph">
<p>To drop (delete) a table, use the <code class="notranslate">drop</code> command.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">hbase(main):011:0&gt; drop 'test'
0 row(s) in 0.1370 seconds</pre>
</div>
</div> </li>
<li> <p>Exit the HBase Shell.</p>
<div class="paragraph">
<p>To exit the HBase Shell and disconnect from your cluster, use the <code class="notranslate">quit</code> command. HBase is still running in the background.</p>
</div> </li>
</ol>
</div>
<div class="olist arabic">
<div class="title">
Procedure: Stop HBase
</div>
<ol class="arabic">
<li> <p>In the same way that the <em>bin/start-hbase.sh</em> script is provided to conveniently start all HBase daemons, the <em>bin/stop-hbase.sh</em> script stops them.</p>
<div class="listingblock">
<div class="content">
<pre class="notranslate">$ ./bin/stop-hbase.sh
stopping hbase....................
$</pre>
</div>
</div> </li>
<li> <p>After issuing the command, it can take several minutes for the processes to shut down. Use the <code class="notranslate">jps</code> to be sure that the HMaster and HRegionServer processes are shut down.</p> </li>
</ol>
</div>
<div class="paragraph">
<p>The above has shown you how to start and stop a standalone instance of HBase. In the next sections we give a quick overview of other modes of hbase deploy.</p>
</div>
</div>
<div class="sect2">
<h3 id="quickstart_pseudo"><a class="anchor" href="#quickstart_pseudo"></a>2.3. Pseudo-Distributed Local Install</h3>
<div class="paragraph">
<p>After working your way through <a href="#quickstart">quickstart</a> standalone mode, you can re-configure HBase to run in pseudo-distributed mode. Pseudo-distributed mode means that HBase still runs completely on a single host, but each HBase daemon (HMaster, HRegionServer, and ZooKeeper) runs as a separate process: in standalone mode all daemons ran in one jvm process/instance. By default, unless you configure the <code class="notranslate">hbase.rootdir</code> property as described in <a href="#quickstart">quickstart</a>, your data is still stored in <em>/tmp/</em>. In this walk-through, we store your data in HDFS instead, assuming you have HDFS available. You can skip the HDFS configuration to continue storing your data in the local filesystem.</p>
</div>
<div class="admonitionblock note">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-note" title="Note"></i> </td>
<td class="content">
<div class="title">
Hadoop Configuration
</div>
<div class="paragraph">
<p>This procedure assumes that you have configured Hadoop and HDFS on your local system and/or a remote system, and that they are running and available. It also assumes you are using Hadoop 2. The guide on <a href="javascript:window.open('https://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-common/SingleCluster.html');" target="_blank" rel="noopener noreferrer">Setting up a Single Node Cluster <i class="fa fa-external-link"></i></a> in the Hadoop documentation is a good starting point.</p>
</div> </td>
</tr>
</tbody>
</table>
</div>
<div class="olist arabic">
<ol class="arabic">
<li> <p>Stop HBase if it is running.</p>
<div class="paragraph">
<p>If you have just finished <a href="#quickstart">quickstart</a> and HBase is still running, stop it. This procedure will create a totally new directory where HBase will store its data, so any databases you created before will be lost.</p>
</div> </li>
<li> <p>Configure HBase.</p>
<div class="paragraph">
<p>Edit the <em>hbase-site.xml</em> configuration. First, add the following property which directs HBase to run in distributed mode, with one JVM instance per daemon.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight notranslate"><code data-lang="xml"><span class="tag">&lt;property&gt;</span>
  <span class="tag">&lt;name&gt;</span>hbase.cluster.distributed<span class="tag">&lt;/name&gt;</span>
  <span class="tag">&lt;value&gt;</span>true<span class="tag">&lt;/value&gt;</span>
<span class="tag">&lt;/property&gt;</span></code></pre>
</div>
</div>
<div class="paragraph">
<p>Next, change the <code class="notranslate">hbase.rootdir</code> from the local filesystem to the address of your HDFS instance, using the <code class="notranslate">hdfs:////</code> URI syntax. In this example, HDFS is running on the localhost at port 8020. Be sure to either remove the entry for <code class="notranslate">hbase.unsafe.stream.capability.enforce</code> or set it to true.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight notranslate"><code data-lang="xml"><span class="tag">&lt;property&gt;</span>
  <span class="tag">&lt;name&gt;</span>hbase.rootdir<span class="tag">&lt;/name&gt;</span>
  <span class="tag">&lt;value&gt;</span>hdfs://localhost:8020/hbase<span class="tag">&lt;/value&gt;</span>
<span class="tag">&lt;/property&gt;</span></code></pre>
</div>
</div>
<div class="paragraph">
<p>You do not need to create the directory in HDFS. HBase will do this for you. If you create the directory, HBase will attempt to do a migration, which is not what you want.</p>
</div> </li>
<li> <p>Start HBase.</p>
<div class="paragraph">
<p>Use the <em>bin/start-hbase.sh</em> command to start HBase. If your system is configured correctly, the <code class="notranslate">jps</code> command should show the HMaster and HRegionServer processes running.</p>
</div> </li>
<li> <p>Check the HBase directory in HDFS.</p>
<div class="paragraph">
<p>If everything worked correctly, HBase created its directory in HDFS. In the configuration above, it is stored in <em>/hbase/</em> on HDFS. You can use the <code class="notranslate">hadoop fs</code> command in Hadoop’s <em>bin/</em> directory to list this directory.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">$ ./bin/hadoop fs -ls /hbase
Found 7 items
drwxr-xr-x   - hbase users          0 2014-06-25 18:58 /hbase/.tmp
drwxr-xr-x   - hbase users          0 2014-06-25 21:49 /hbase/WALs
drwxr-xr-x   - hbase users          0 2014-06-25 18:48 /hbase/corrupt
drwxr-xr-x   - hbase users          0 2014-06-25 18:58 /hbase/data
-rw-r--r--   3 hbase users         42 2014-06-25 18:41 /hbase/hbase.id
-rw-r--r--   3 hbase users          7 2014-06-25 18:41 /hbase/hbase.version
drwxr-xr-x   - hbase users          0 2014-06-25 21:49 /hbase/oldWALs</pre>
</div>
</div> </li>
<li> <p>Create a table and populate it with data.</p>
<div class="paragraph">
<p>You can use the HBase Shell to create a table, populate it with data, scan and get values from it, using the same procedure as in <a href="#shell_exercises">shell exercises</a>.</p>
</div> </li>
<li> <p>Start and stop a backup HBase Master (HMaster) server.</p>
<div class="admonitionblock note">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-note" title="Note"></i> </td>
<td class="content"> Running multiple HMaster instances on the same hardware does not make sense in a production environment, in the same way that running a pseudo-distributed cluster does not make sense for production. This step is offered for testing and learning purposes only. </td>
</tr>
</tbody>
</table>
</div>
<div class="paragraph">
<p>The HMaster server controls the HBase cluster. You can start up to 9 backup HMaster servers, which makes 10 total HMasters, counting the primary. To start a backup HMaster, use the <code class="notranslate">local-master-backup.sh</code>. For each backup master you want to start, add a parameter representing the port offset for that master. Each HMaster uses two ports (16000 and 16010 by default). The port offset is added to these ports, so using an offset of 2, the backup HMaster would use ports 16002 and 16012. The following command starts 3 backup servers using ports 16002/16012, 16003/16013, and 16005/16015.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">$ ./bin/local-master-backup.sh start 2 3 5</pre>
</div>
</div>
<div class="paragraph">
<p>To kill a backup master without killing the entire cluster, you need to find its process ID (PID). The PID is stored in a file with a name like <em>/tmp/hbase-USER-X-master.pid</em>. The only contents of the file is the PID. You can use the <code class="notranslate">kill -9</code> command to kill that PID. The following command will kill the master with port offset 1, but leave the cluster running:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">$ cat /tmp/hbase-testuser-1-master.pid |xargs kill -9</pre>
</div>
</div> </li>
<li> <p>Start and stop additional RegionServers</p>
<div class="paragraph">
<p>The HRegionServer manages the data in its StoreFiles as directed by the HMaster. Generally, one HRegionServer runs per node in the cluster. Running multiple HRegionServers on the same system can be useful for testing in pseudo-distributed mode. The <code class="notranslate">local-regionservers.sh</code> command allows you to run multiple RegionServers. It works in a similar way to the <code class="notranslate">local-master-backup.sh</code> command, in that each parameter you provide represents the port offset for an instance. Each RegionServer requires two ports, and the default ports are 16020 and 16030. Since HBase version 1.1.0, HMaster doesn’t use region server ports, this leaves 10 ports (16020 to 16029 and 16030 to 16039) to be used for RegionServers. For supporting additional RegionServers, set environment variables HBASE_RS_BASE_PORT and HBASE_RS_INFO_BASE_PORT to appropriate values before running script <code class="notranslate">local-regionservers.sh</code>. e.g. With values 16200 and 16300 for base ports, 99 additional RegionServers can be supported, on a server. The following command starts four additional RegionServers, running on sequential ports starting at 16022/16032 (base ports 16020/16030 plus 2).</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">$ .bin/local-regionservers.sh start 2 3 4 5</pre>
</div>
</div>
<div class="paragraph">
<p>To stop a RegionServer manually, use the <code class="notranslate">local-regionservers.sh</code> command with the <code class="notranslate">stop</code> parameter and the offset of the server to stop.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">$ .bin/local-regionservers.sh stop 3</pre>
</div>
</div> </li>
<li> <p>Stop HBase.</p>
<div class="paragraph">
<p>You can stop HBase the same way as in the <a href="#quickstart">quickstart</a> procedure, using the <em>bin/stop-hbase.sh</em> command.</p>
</div> </li>
</ol>
</div>
</div>
<div class="sect2">
<h3 id="quickstart_fully_distributed"><a class="anchor" href="#quickstart_fully_distributed"></a>2.4. Advanced - Fully Distributed</h3>
<div class="paragraph">
<p>In reality, you need a fully-distributed configuration to fully test HBase and to use it in real-world scenarios. In a distributed configuration, the cluster contains multiple nodes, each of which runs one or more HBase daemon. These include primary and backup Master instances, multiple ZooKeeper nodes, and multiple RegionServer nodes.</p>
</div>
<div class="paragraph">
<p>This advanced quickstart adds two more nodes to your cluster. The architecture will be as follows:</p>
</div>
<table class="tableblock frame-all grid-all spread">
<caption class="title">
Table 1. Distributed Cluster Demo Architecture
</caption>
<colgroup>
<col style="width: 25%;">
<col style="width: 25%;">
<col style="width: 25%;">
<col style="width: 25%;">
</colgroup>
<thead>
<tr>
<th class="tableblock halign-left valign-top">Node Name</th>
<th class="tableblock halign-left valign-top">Master</th>
<th class="tableblock halign-left valign-top">ZooKeeper</th>
<th class="tableblock halign-left valign-top">RegionServer</th>
</tr>
</thead>
<tbody>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">node-a.example.com</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">yes</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">yes</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">no</p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">node-b.example.com</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">backup</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">yes</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">yes</p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">node-c.example.com</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">no</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">yes</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">yes</p></td>
</tr>
</tbody>
</table>
<div class="paragraph">
<p>This quickstart assumes that each node is a virtual machine and that they are all on the same network. It builds upon the previous quickstart, <a href="#quickstart_pseudo">Pseudo-Distributed Local Install</a>, assuming that the system you configured in that procedure is now <code class="notranslate">node-a</code>. Stop HBase on <code class="notranslate">node-a</code> before continuing.</p>
</div>
<div class="admonitionblock note">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-note" title="Note"></i> </td>
<td class="content"> Be sure that all the nodes have full access to communicate, and that no firewall rules are in place which could prevent them from talking to each other. If you see any errors like <code class="notranslate">no route to host</code>, check your firewall. </td>
</tr>
</tbody>
</table>
</div>
<div id="passwordless.ssh.quickstart" class="paragraph">
<div class="title">
Procedure: Configure Passwordless SSH Access
</div>
<p><code class="notranslate">node-a</code> needs to be able to log into <code class="notranslate">node-b</code> and <code class="notranslate">node-c</code> (and to itself) in order to start the daemons. The easiest way to accomplish this is to use the same username on all hosts, and configure password-less SSH login from <code class="notranslate">node-a</code> to each of the others.</p>
</div>
<div class="olist arabic">
<ol class="arabic">
<li> <p>On <code class="notranslate">node-a</code>, generate a key pair.</p>
<div class="paragraph">
<p>While logged in as the user who will run HBase, generate a SSH key pair, using the following command:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight notranslate"><code data-lang="bash">$ ssh-keygen -t rsa</code></pre>
</div>
</div>
<div class="paragraph">
<p>If the command succeeds, the location of the key pair is printed to standard output. The default name of the public key is <em>id_rsa.pub</em>.</p>
</div> </li>
<li> <p>Create the directory that will hold the shared keys on the other nodes.</p>
<div class="paragraph">
<p>On <code class="notranslate">node-b</code> and <code class="notranslate">node-c</code>, log in as the HBase user and create a <em>.ssh/</em> directory in the user’s home directory, if it does not already exist. If it already exists, be aware that it may already contain other keys.</p>
</div> </li>
<li> <p>Copy the public key to the other nodes.</p>
<div class="paragraph">
<p>Securely copy the public key from <code class="notranslate">node-a</code> to each of the nodes, by using the <code class="notranslate">scp</code> or some other secure means. On each of the other nodes, create a new file called <em>.ssh/authorized_keys</em> <em>if it does not already exist</em>, and append the contents of the <em>id_rsa.pub</em> file to the end of it. Note that you also need to do this for <code class="notranslate">node-a</code> itself.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">$ cat id_rsa.pub &gt;&gt; ~/.ssh/authorized_keys</pre>
</div>
</div> </li>
<li> <p>Test password-less login.</p>
<div class="paragraph">
<p>If you performed the procedure correctly, you should not be prompted for a password when you SSH from <code class="notranslate">node-a</code> to either of the other nodes using the same username.</p>
</div> </li>
<li> <p>Since <code class="notranslate">node-b</code> will run a backup Master, repeat the procedure above, substituting <code class="notranslate">node-b</code> everywhere you see <code class="notranslate">node-a</code>. Be sure not to overwrite your existing <em>.ssh/authorized_keys</em> files, but concatenate the new key onto the existing file using the <code class="notranslate">&gt;&gt;</code> operator rather than the <code class="notranslate">&gt;</code> operator.</p> </li>
</ol>
</div>
<div class="paragraph">
<div class="title">
Procedure: Prepare
<code class="notranslate">node-a</code>
</div>
<p><code class="notranslate">node-a</code> will run your primary master and ZooKeeper processes, but no RegionServers. Stop the RegionServer from starting on <code class="notranslate">node-a</code>.</p>
</div>
<div class="olist arabic">
<ol class="arabic">
<li> <p>Edit <em>conf/regionservers</em> and remove the line which contains <code class="notranslate">localhost</code>. Add lines with the hostnames or IP addresses for <code class="notranslate">node-b</code> and <code class="notranslate">node-c</code>.</p>
<div class="paragraph">
<p>Even if you did want to run a RegionServer on <code class="notranslate">node-a</code>, you should refer to it by the hostname the other servers would use to communicate with it. In this case, that would be <code class="notranslate">node-a.example.com</code>. This enables you to distribute the configuration to each node of your cluster any hostname conflicts. Save the file.</p>
</div> </li>
<li> <p>Configure HBase to use <code class="notranslate">node-b</code> as a backup master.</p>
<div class="paragraph">
<p>Create a new file in <em>conf/</em> called <em>backup-masters</em>, and add a new line to it with the hostname for <code class="notranslate">node-b</code>. In this demonstration, the hostname is <code class="notranslate">node-b.example.com</code>.</p>
</div> </li>
<li> <p>Configure ZooKeeper</p>
<div class="paragraph">
<p>In reality, you should carefully consider your ZooKeeper configuration. You can find out more about configuring ZooKeeper in <a href="#zookeeper">zookeeper</a> section. This configuration will direct HBase to start and manage a ZooKeeper instance on each node of the cluster.</p>
</div>
<div class="paragraph">
<p>On <code class="notranslate">node-a</code>, edit <em>conf/hbase-site.xml</em> and add the following properties.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight notranslate"><code data-lang="xml"><span class="tag">&lt;property&gt;</span>
  <span class="tag">&lt;name&gt;</span>hbase.zookeeper.quorum<span class="tag">&lt;/name&gt;</span>
  <span class="tag">&lt;value&gt;</span>node-a.example.com,node-b.example.com,node-c.example.com<span class="tag">&lt;/value&gt;</span>
<span class="tag">&lt;/property&gt;</span>
<span class="tag">&lt;property&gt;</span>
  <span class="tag">&lt;name&gt;</span>hbase.zookeeper.property.dataDir<span class="tag">&lt;/name&gt;</span>
  <span class="tag">&lt;value&gt;</span>/usr/local/zookeeper<span class="tag">&lt;/value&gt;</span>
<span class="tag">&lt;/property&gt;</span></code></pre>
</div>
</div> </li>
<li> <p>Everywhere in your configuration that you have referred to <code class="notranslate">node-a</code> as <code class="notranslate">localhost</code>, change the reference to point to the hostname that the other nodes will use to refer to <code class="notranslate">node-a</code>. In these examples, the hostname is <code class="notranslate">node-a.example.com</code>.</p> </li>
</ol>
</div>
<div class="paragraph">
<div class="title">
Procedure: Prepare
<code class="notranslate">node-b</code> and
<code class="notranslate">node-c</code>
</div>
<p><code class="notranslate">node-b</code> will run a backup master server and a ZooKeeper instance.</p>
</div>
<div class="olist arabic">
<ol class="arabic">
<li> <p>Download and unpack HBase.</p>
<div class="paragraph">
<p>Download and unpack HBase to <code class="notranslate">node-b</code>, just as you did for the standalone and pseudo-distributed quickstarts.</p>
</div> </li>
<li> <p>Copy the configuration files from <code class="notranslate">node-a</code> to <code class="notranslate">node-b</code>.and <code class="notranslate">node-c</code>.</p>
<div class="paragraph">
<p>Each node of your cluster needs to have the same configuration information. Copy the contents of the <em>conf/</em> directory to the <em>conf/</em> directory on <code class="notranslate">node-b</code> and <code class="notranslate">node-c</code>.</p>
</div> </li>
</ol>
</div>
<div class="olist arabic">
<div class="title">
Procedure: Start and Test Your Cluster
</div>
<ol class="arabic">
<li> <p>Be sure HBase is not running on any node.</p>
<div class="paragraph">
<p>If you forgot to stop HBase from previous testing, you will have errors. Check to see whether HBase is running on any of your nodes by using the <code class="notranslate">jps</code> command. Look for the processes <code class="notranslate">HMaster</code>, <code class="notranslate">HRegionServer</code>, and <code class="notranslate">HQuorumPeer</code>. If they exist, kill them.</p>
</div> </li>
<li> <p>Start the cluster.</p>
<div class="paragraph">
<p>On <code class="notranslate">node-a</code>, issue the <code class="notranslate">start-hbase.sh</code> command. Your output will be similar to that below.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">$ bin/start-hbase.sh
node-c.example.com: starting zookeeper, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-zookeeper-node-c.example.com.out
node-a.example.com: starting zookeeper, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-zookeeper-node-a.example.com.out
node-b.example.com: starting zookeeper, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-zookeeper-node-b.example.com.out
starting master, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-master-node-a.example.com.out
node-c.example.com: starting regionserver, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-regionserver-node-c.example.com.out
node-b.example.com: starting regionserver, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-regionserver-node-b.example.com.out
node-b.example.com: starting master, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-master-nodeb.example.com.out</pre>
</div>
</div>
<div class="paragraph">
<p>ZooKeeper starts first, followed by the master, then the RegionServers, and finally the backup masters.</p>
</div> </li>
<li> <p>Verify that the processes are running.</p>
<div class="paragraph">
<p>On each node of the cluster, run the <code class="notranslate">jps</code> command and verify that the correct processes are running on each server. You may see additional Java processes running on your servers as well, if they are used for other purposes.</p>
</div>
<div class="listingblock">
<div class="title">
<code class="notranslate">node-a</code>
<code class="notranslate">jps</code> Output
</div>
<div class="content">
<pre class="notranslate">$ jps
20355 Jps
20071 HQuorumPeer
20137 HMaster</pre>
</div>
</div>
<div class="listingblock">
<div class="title">
<code class="notranslate">node-b</code>
<code class="notranslate">jps</code> Output
</div>
<div class="content">
<pre class="notranslate">$ jps
15930 HRegionServer
16194 Jps
15838 HQuorumPeer
16010 HMaster</pre>
</div>
</div>
<div class="listingblock">
<div class="title">
<code class="notranslate">node-c</code>
<code class="notranslate">jps</code> Output
</div>
<div class="content">
<pre class="notranslate">$ jps
13901 Jps
13639 HQuorumPeer
13737 HRegionServer</pre>
</div>
</div>
<div class="admonitionblock note">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-note" title="Note"></i> </td>
<td class="content">
<div class="title">
ZooKeeper Process Name
</div>
<div class="paragraph">
<p>The <code class="notranslate">HQuorumPeer</code> process is a ZooKeeper instance which is controlled and started by HBase. If you use ZooKeeper this way, it is limited to one instance per cluster node and is appropriate for testing only. If ZooKeeper is run outside of HBase, the process is called <code class="notranslate">QuorumPeer</code>. For more about ZooKeeper configuration, including using an external ZooKeeper instance with HBase, see <a href="#zookeeper">zookeeper</a> section.</p>
</div> </td>
</tr>
</tbody>
</table>
</div> </li>
<li> <p>Browse to the Web UI.</p>
<div class="admonitionblock note">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-note" title="Note"></i> </td>
<td class="content">
<div class="title">
Web UI Port Changes
</div> Web UI Port Changes </td>
</tr>
</tbody>
</table>
</div>
<div class="paragraph">
<p>In HBase newer than 0.98.x, the HTTP ports used by the HBase Web UI changed from 60010 for the Master and 60030 for each RegionServer to 16010 for the Master and 16030 for the RegionServer.</p>
</div>
<div class="paragraph">
<p>If everything is set up correctly, you should be able to connect to the UI for the Master <code class="notranslate"><a href="javascript:window.open('http://node-a.example.com:16010/');" class="bare" target="_blank" rel="noopener noreferrer">http://node-a.example.com:16010/ <i class="fa fa-external-link"></i></a></code> or the secondary master at <code class="notranslate"><a href="javascript:window.open('http://node-b.example.com:16010/');" class="bare" target="_blank" rel="noopener noreferrer">http://node-b.example.com:16010/ <i class="fa fa-external-link"></i></a></code> using a web browser. If you can connect via <code class="notranslate">localhost</code> but not from another host, check your firewall rules. You can see the web UI for each of the RegionServers at port 16030 of their IP addresses, or by clicking their links in the web UI for the Master.</p>
</div> </li>
<li> <p>Test what happens when nodes or services disappear.</p>
<div class="paragraph"> 
<p>With a three-node cluster you have configured, things will not be very resilient. You can still test the behavior of the primary Master or a RegionServer by killing the associated processes and watching the logs.</p>
</div> </li>
</ol>
</div>
</div>
<div class="sect2">
<h3 id="_where_to_go_next"><a class="anchor" href="#_where_to_go_next"></a>2.5. Where to go next</h3>
<div class="paragraph">
<p>The next chapter, <a href="#configuration">configuration</a>, gives more information about the different HBase run modes, system requirements for running HBase, and critical configuration areas for setting up a distributed HBase cluster.</p>
</div>
</div>
</div>
</div>
<h2 id="configuration" class="sect0"><a class="anchor" href="#configuration"></a>Apache HBase Configuration</h2>
<div class="openblock partintro">
<div class="content">
This chapter expands upon the
<a href="#getting_started">Getting Started</a> chapter to further explain configuration of Apache HBase. Please read this chapter carefully, especially the
<a href="#basic.prerequisites">Basic Prerequisites</a> to ensure that your HBase testing and deployment goes smoothly. Familiarize yourself with
<a href="#hbase_supported_tested_definitions">Support and Testing Expectations</a> as well.
</div>
</div>
<div class="sect1">
<h2 id="_configuration_files"><a class="anchor" href="#_configuration_files"></a>3. Configuration Files</h2>
<div class="sectionbody">
<div class="paragraph">
<p>Apache HBase uses the same configuration system as Apache Hadoop. All configuration files are located in the <em>conf/</em> directory, which needs to be kept in sync for each node on your cluster.</p>
</div>
<div class="dlist">
<div class="title">
HBase Configuration File Descriptions
</div>
<dl>
<dt class="hdlist1">
<em>backup-masters</em>
</dt>
<dd>
<p>Not present by default. A plain-text file which lists hosts on which the Master should start a backup Master process, one host per line.</p>
</dd>
<dt class="hdlist1">
<em>hadoop-metrics2-hbase.properties</em>
</dt>
<dd>
<p>Used to connect HBase Hadoop’s Metrics2 framework. See the <a href="javascript:window.open('https://wiki.apache.org/hadoop/HADOOP-6728-MetricsV2');" target="_blank" rel="noopener noreferrer">Hadoop Wiki entry <i class="fa fa-external-link"></i></a> for more information on Metrics2. Contains only commented-out examples by default.</p>
</dd>
<dt class="hdlist1">
<em>hbase-env.cmd</em> and
<em>hbase-env.sh</em>
</dt>
<dd>
<p>Script for Windows and Linux / Unix environments to set up the working environment for HBase, including the location of Java, Java options, and other environment variables. The file contains many commented-out examples to provide guidance.</p>
</dd>
<dt class="hdlist1">
<em>hbase-policy.xml</em>
</dt>
<dd>
<p>The default policy configuration file used by RPC servers to make authorization decisions on client requests. Only used if HBase <a href="#security">security</a> is enabled.</p>
</dd>
<dt class="hdlist1">
<em>hbase-site.xml</em>
</dt>
<dd>
<p>The main HBase configuration file. This file specifies configuration options which override HBase’s default configuration. You can view (but do not edit) the default configuration file at <em>docs/hbase-default.xml</em>. You can also view the entire effective configuration for your cluster (defaults and overrides) in the <span class="label">HBase Configuration</span> tab of the HBase Web UI.</p>
</dd>
<dt class="hdlist1">
<em>log4j.properties</em>
</dt>
<dd>
<p>Configuration file for HBase logging via <code class="notranslate">log4j</code>.</p>
</dd>
<dt class="hdlist1">
<em>regionservers</em>
</dt>
<dd>
<p>A plain-text file containing a list of hosts which should run a RegionServer in your HBase cluster. By default this file contains the single entry <code class="notranslate">localhost</code>. It should contain a list of hostnames or IP addresses, one per line, and should only contain <code class="notranslate">localhost</code> if each node in your cluster will run a RegionServer on its <code class="notranslate">localhost</code> interface.</p>
</dd>
</dl>
</div>
<div class="admonitionblock tip">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-tip" title="Tip"></i> </td>
<td class="content">
<div class="title">
Checking XML Validity
</div>
<div class="paragraph">
<p>When you edit XML, it is a good idea to use an XML-aware editor to be sure that your syntax is correct and your XML is well-formed. You can also use the <code class="notranslate">xmllint</code> utility to check that your XML is well-formed. By default, <code class="notranslate">xmllint</code> re-flows and prints the XML to standard output. To check for well-formedness and only print output if errors exist, use the command <code class="notranslate">xmllint -noout filename.xml</code>.</p>
</div> </td>
</tr>
</tbody>
</table>
</div>
<div class="admonitionblock warning">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-warning" title="Warning"></i> </td>
<td class="content">
<div class="title">
Keep Configuration In Sync Across the Cluster
</div>
<div class="paragraph">
<p>When running in distributed mode, after you make an edit to an HBase configuration, make sure you copy the contents of the <em>conf/</em> directory to all nodes of the cluster. HBase will not do this for you. Use <code class="notranslate">rsync</code>, <code class="notranslate">scp</code>, or another secure mechanism for copying the configuration files to your nodes. For most configurations, a restart is needed for servers to pick up changes. Dynamic configuration is an exception to this, to be described later below.</p>
</div> </td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
<div class="sect1">
<h2 id="basic.prerequisites"><a class="anchor" href="#basic.prerequisites"></a>4. Basic Prerequisites</h2>
<div class="sectionbody">
<div class="paragraph">
<p>This section lists required services and some required system configuration.</p>
</div>
<div id="java" class="paragraph">
<div class="title">
Java
</div>
<p>The following table summarizes the recommendation of the HBase community wrt deploying on various Java versions. An entry of "yes" is meant to indicate a base level of testing and willingness to help diagnose and address issues you might run into. Similarly, an entry of "no" or "Not Supported" generally means that should you run into an issue the community is likely to ask you to change the Java environment before proceeding to help. In some cases, specific guidance on limitations (e.g. wether compiling / unit tests work, specific operational issues, etc) will also be noted.</p>
</div>
<div class="admonitionblock tip">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-tip" title="Tip"></i> </td>
<td class="content">
<div class="title">
Long Term Support JDKs are recommended
</div>
<div class="paragraph">
<p>HBase recommends downstream users rely on JDK releases that are marked as Long Term Supported (LTS) either from the OpenJDK project or vendors. As of March 2018 that means Java 8 is the only applicable version and that the next likely version to see testing will be Java 11 near Q3 2018.</p>
</div> </td>
</tr>
</tbody>
</table>
</div>
<table class="tableblock frame-all grid-all spread">
<caption class="title">
Table 2. Java support by release line
</caption>
<colgroup>
<col style="width: 20%;">
<col style="width: 20%;">
<col style="width: 20%;">
<col style="width: 20%;">
<col style="width: 20%;">
</colgroup>
<thead>
<tr>
<th class="tableblock halign-left valign-top">HBase Version</th>
<th class="tableblock halign-left valign-top">JDK 7</th>
<th class="tableblock halign-left valign-top">JDK 8</th>
<th class="tableblock halign-left valign-top">JDK 9</th>
<th class="tableblock halign-left valign-top">JDK 10</th>
</tr>
</thead>
<tbody>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">2.0</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock"><a href="javascript:window.open('http://search-hadoop.com/m/YGbbsPxZ723m3as');" target="_blank" rel="noopener noreferrer">Not Supported <i class="fa fa-external-link"></i></a></p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">yes</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock"><a href="javascript:window.open('https://issues.apache.org/jira/browse/HBASE-20264');" target="_blank" rel="noopener noreferrer">Not Supported <i class="fa fa-external-link"></i></a></p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock"><a href="javascript:window.open('https://issues.apache.org/jira/browse/HBASE-20264');" target="_blank" rel="noopener noreferrer">Not Supported <i class="fa fa-external-link"></i></a></p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">1.3</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">yes</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">yes</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock"><a href="javascript:window.open('https://issues.apache.org/jira/browse/HBASE-20264');" target="_blank" rel="noopener noreferrer">Not Supported <i class="fa fa-external-link"></i></a></p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock"><a href="javascript:window.open('https://issues.apache.org/jira/browse/HBASE-20264');" target="_blank" rel="noopener noreferrer">Not Supported <i class="fa fa-external-link"></i></a></p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">1.2</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">yes</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">yes</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock"><a href="javascript:window.open('https://issues.apache.org/jira/browse/HBASE-20264');" target="_blank" rel="noopener noreferrer">Not Supported <i class="fa fa-external-link"></i></a></p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock"><a href="javascript:window.open('https://issues.apache.org/jira/browse/HBASE-20264');" target="_blank" rel="noopener noreferrer">Not Supported <i class="fa fa-external-link"></i></a></p></td>
</tr>
</tbody>
</table>
<div class="admonitionblock note">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-note" title="Note"></i> </td>
<td class="content"> HBase will neither build nor run with Java 6. </td>
</tr>
</tbody>
</table>
</div>
<div class="admonitionblock note">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-note" title="Note"></i> </td>
<td class="content"> You must set <code class="notranslate">JAVA_HOME</code> on each node of your cluster. <em>hbase-env.sh</em> provides a handy mechanism to do this. </td>
</tr>
</tbody>
</table>
</div>
<div id="os" class="dlist">
<div class="title">
Operating System Utilities
</div>
<dl>
<dt class="hdlist1">
ssh
</dt>
<dd>
<p>HBase uses the Secure Shell (ssh) command and utilities extensively to communicate between cluster nodes. Each server in the cluster must be running <code class="notranslate">ssh</code> so that the Hadoop and HBase daemons can be managed. You must be able to connect to all nodes via SSH, including the local node, from the Master as well as any backup Master, using a shared key rather than a password. You can see the basic methodology for such a set-up in Linux or Unix systems at "<a href="#passwordless.ssh.quickstart">Procedure: Configure Passwordless SSH Access</a>". If your cluster nodes use OS X, see the section, <a href="javascript:window.open('https://wiki.apache.org/hadoop/Running_Hadoop_On_OS_X_10.5_64-bit_(Single-Node_Cluster)');" target="_blank" rel="noopener noreferrer">SSH: Setting up Remote Desktop and Enabling Self-Login <i class="fa fa-external-link"></i></a> on the Hadoop wiki.</p>
</dd>
<dt class="hdlist1">
DNS
</dt>
<dd>
<p>HBase uses the local hostname to self-report its IP address.</p>
</dd>
<dt class="hdlist1">
NTP
</dt>
<dd>
<p>The clocks on cluster nodes should be synchronized. A small amount of variation is acceptable, but larger amounts of skew can cause erratic and unexpected behavior. Time synchronization is one of the first things to check if you see unexplained problems in your cluster. It is recommended that you run a Network Time Protocol (NTP) service, or another time-synchronization mechanism on your cluster and that all nodes look to the same service for time synchronization. See the <a href="javascript:window.open('http://www.tldp.org/LDP/sag/html/basic-ntp-config.html');" target="_blank" rel="noopener noreferrer">Basic NTP Configuration <i class="fa fa-external-link"></i></a> at <em class="citetitle">The Linux Documentation Project (TLDP)</em> to set up NTP.</p>
</dd>
</dl>
</div>
<div id="ulimit" class="dlist">
<dl>
<dt class="hdlist1">
Limits on Number of Files and Processes (ulimit)
</dt>
<dd>
<p>Apache HBase is a database. It requires the ability to open a large number of files at once. Many Linux distributions limit the number of files a single user is allowed to open to <code class="notranslate">1024</code> (or <code class="notranslate">256</code> on older versions of OS X). You can check this limit on your servers by running the command <code class="notranslate">ulimit -n</code> when logged in as the user which runs HBase. See <a href="#trouble.rs.runtime.filehandles">the Troubleshooting section</a> for some of the problems you may experience if the limit is too low. You may also notice errors such as the following:</p>
<div class="listingblock">
<div class="content">
<pre class="notranslate">2010-04-06 03:04:37,542 INFO org.apache.hadoop.hdfs.DFSClient: Exception increateBlockOutputStream java.io.EOFException
2010-04-06 03:04:37,542 INFO org.apache.hadoop.hdfs.DFSClient: Abandoning block blk_-6935524980745310745_1391901</pre>
</div>
</div>
<div class="paragraph">
<p>It is recommended to raise the ulimit to at least 10,000, but more likely 10,240, because the value is usually expressed in multiples of 1024. Each ColumnFamily has at least one StoreFile, and possibly more than six StoreFiles if the region is under load. The number of open files required depends upon the number of ColumnFamilies and the number of regions. The following is a rough formula for calculating the potential number of open files on a RegionServer.</p>
</div>
<div class="listingblock">
<div class="title">
Calculate the Potential Number of Open Files
</div>
<div class="content">
<pre class="notranslate">(StoreFiles per ColumnFamily) x (regions per RegionServer)</pre>
</div>
</div>
<div class="paragraph">
<p>For example, assuming that a schema had 3 ColumnFamilies per region with an average of 3 StoreFiles per ColumnFamily, and there are 100 regions per RegionServer, the JVM will open <code class="notranslate">3 * 3 * 100 = 900</code> file descriptors, not counting open JAR files, configuration files, and others. Opening a file does not take many resources, and the risk of allowing a user to open too many files is minimal.</p>
</div>
<div class="paragraph">
<p>Another related setting is the number of processes a user is allowed to run at once. In Linux and Unix, the number of processes is set using the <code class="notranslate">ulimit -u</code> command. This should not be confused with the <code class="notranslate">nproc</code> command, which controls the number of CPUs available to a given user. Under load, a <code class="notranslate">ulimit -u</code> that is too low can cause OutOfMemoryError exceptions.</p>
</div>
<div class="paragraph">
<p>Configuring the maximum number of file descriptors and processes for the user who is running the HBase process is an operating system configuration, rather than an HBase configuration. It is also important to be sure that the settings are changed for the user that actually runs HBase. To see which user started HBase, and that user’s ulimit configuration, look at the first line of the HBase log for that instance.</p>
</div>
<div class="exampleblock">
<div class="title">
Example 2.
<code class="notranslate">ulimit</code> Settings on Ubuntu
</div>
<div class="content">
<div class="paragraph">
<p>To configure ulimit settings on Ubuntu, edit <em>/etc/security/limits.conf</em>, which is a space-delimited file with four columns. Refer to the man page for <em>limits.conf</em> for details about the format of this file. In the following example, the first line sets both soft and hard limits for the number of open files (nofile) to 32768 for the operating system user with the username hadoop. The second line sets the number of processes to 32000 for the same user.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">hadoop  -       nofile  32768
hadoop  -       nproc   32000</pre>
</div>
</div>
<div class="paragraph">
<p>The settings are only applied if the Pluggable Authentication Module (PAM) environment is directed to use them. To configure PAM to use these limits, be sure that the <em>/etc/pam.d/common-session</em> file contains the following line:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">session required  pam_limits.so</pre>
</div>
</div>
</div>
</div>
</dd>
<dt class="hdlist1">
Linux Shell
</dt>
<dd>
<p>All of the shell scripts that come with HBase rely on the <a href="javascript:window.open('https://www.gnu.org/software/bash');" target="_blank" rel="noopener noreferrer">GNU Bash <i class="fa fa-external-link"></i></a> shell.</p>
</dd>
<dt class="hdlist1">
Windows
</dt>
<dd>
<p>Running production systems on Windows machines is not recommended.</p>
</dd>
</dl>
</div>
<div class="sect2">
<h3 id="hadoop"><a class="anchor" href="#hadoop"></a>4.1. <a href="javascript:window.open('https://hadoop.apache.org/');" target="_blank" rel="noopener noreferrer">Hadoop <i class="fa fa-external-link"></i></a></h3>
<div class="paragraph">
<p>The following table summarizes the versions of Hadoop supported with each version of HBase. Older versions not appearing in this table are considered unsupported and likely missing necessary features, while newer versions are untested but may be suitable.</p>
</div>
<div class="paragraph">
<p>Based on the version of HBase, you should select the most appropriate version of Hadoop. You can use Apache Hadoop, or a vendor’s distribution of Hadoop. No distinction is made here. See <a href="javascript:window.open('https://wiki.apache.org/hadoop/Distributions and Commercial Support');" target="_blank" rel="noopener noreferrer">the Hadoop wiki <i class="fa fa-external-link"></i></a> for information about vendors of Hadoop.</p>
</div>
<div class="admonitionblock tip">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-tip" title="Tip"></i> </td>
<td class="content">
<div class="title">
Hadoop 2.x is recommended.
</div>
<div class="paragraph">
<p>Hadoop 2.x is faster and includes features, such as short-circuit reads (see <a href="#perf.hdfs.configs.localread">Leveraging local data</a>), which will help improve your HBase random read profile. Hadoop 2.x also includes important bug fixes that will improve your overall HBase experience. HBase does not support running with earlier versions of Hadoop. See the table below for requirements specific to different HBase versions.</p>
</div>
<div class="paragraph">
<p>Hadoop 3.x is still in early access releases and has not yet been sufficiently tested by the HBase community for production use cases.</p>
</div> </td>
</tr>
</tbody>
</table>
</div>
<div class="paragraph">
<p>Use the following legend to interpret this table:</p>
</div>
<div class="ulist">
<div class="title">
Hadoop version support matrix
</div>
<ul>
<li> <p>"S" = supported</p> </li>
<li> <p>"X" = not supported</p> </li>
<li> <p>"NT" = Not tested</p> </li>
</ul>
</div>
<table class="tableblock frame-all grid-all spread">
<colgroup>
<col style="width: 16.6666%;">
<col style="width: 16.6666%;">
<col style="width: 16.6666%;">
<col style="width: 16.6666%;">
<col style="width: 16.6666%;">
<col style="width: 16.667%;">
</colgroup>
<thead>
<tr>
<th class="tableblock halign-left valign-top"></th>
<th class="tableblock halign-left valign-top">HBase-1.2.x</th>
<th class="tableblock halign-left valign-top">HBase-1.3.x</th>
<th class="tableblock halign-left valign-top">HBase-1.5.x</th>
<th class="tableblock halign-left valign-top">HBase-2.0.x</th>
<th class="tableblock halign-left valign-top">HBase-2.1.x</th>
</tr>
</thead>
<tbody>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">Hadoop-2.4.x</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">Hadoop-2.5.x</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">Hadoop-2.6.0</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">Hadoop-2.6.1+</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">Hadoop-2.7.0</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">Hadoop-2.7.1+</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">Hadoop-2.8.[0-1]</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">Hadoop-2.8.2</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">NT</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">NT</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">NT</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">NT</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">NT</p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">Hadoop-2.8.3+</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">NT</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">NT</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">NT</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">S</p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">Hadoop-2.9.0</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">Hadoop-2.9.1+</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">NT</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">NT</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">NT</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">NT</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">NT</p></td>
 </tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">Hadoop-3.0.x</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
</tr>
<tr>
<td class="tableblock halign-left valign-top"><p class="tableblock">Hadoop-3.1.0</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
<td class="tableblock halign-left valign-top"><p class="tableblock">X</p></td>
</tr>
</tbody>
</table>
<div class="admonitionblock tip">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-tip" title="Tip"></i> </td>
<td class="content">
<div class="title">
Hadoop Pre-2.6.1 and JDK 1.8 Kerberos
</div>
<div class="paragraph">
<p>When using pre-2.6.1 Hadoop versions and JDK 1.8 in a Kerberos environment, HBase server can fail and abort due to Kerberos keytab relogin error. Late version of JDK 1.7 (1.7.0_80) has the problem too. Refer to <a href="javascript:window.open('https://issues.apache.org/jira/browse/HADOOP-10786');" target="_blank" rel="noopener noreferrer">HADOOP-10786 <i class="fa fa-external-link"></i></a> for additional details. Consider upgrading to Hadoop 2.6.1+ in this case.</p>
</div> </td>
</tr>
</tbody>
</table>
</div>
<div class="admonitionblock tip">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-tip" title="Tip"></i> </td>
<td class="content">
<div class="title">
Hadoop 2.6.x
</div>
<div class="paragraph">
<p>Hadoop distributions based on the 2.6.x line <strong>must</strong> have <a href="javascript:window.open('https://issues.apache.org/jira/browse/HADOOP-11710');" target="_blank" rel="noopener noreferrer">HADOOP-11710 <i class="fa fa-external-link"></i></a> applied if you plan to run HBase on top of an HDFS Encryption Zone. Failure to do so will result in cluster failure and data loss. This patch is present in Apache Hadoop releases 2.6.1+.</p>
</div> </td>
</tr>
</tbody>
</table>
</div>
<div class="admonitionblock tip">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-tip" title="Tip"></i> </td>
<td class="content">
<div class="title">
Hadoop 2.y.0 Releases
</div>
<div class="paragraph">
<p>Starting around the time of Hadoop version 2.7.0, the Hadoop PMC got into the habit of calling out new minor releases on their major version 2 release line as not stable / production ready. As such, HBase expressly advises downstream users to avoid running on top of these releases. Note that additionally the 2.8.1 release was given the same caveat by the Hadoop PMC. For reference, see the release announcements for <a href="javascript:window.open('https://s.apache.org/hadoop-2.7.0-announcement');" target="_blank" rel="noopener noreferrer">Apache Hadoop 2.7.0 <i class="fa fa-external-link"></i></a>, <a href="javascript:window.open('https://s.apache.org/hadoop-2.8.0-announcement');" target="_blank" rel="noopener noreferrer">Apache Hadoop 2.8.0 <i class="fa fa-external-link"></i></a>, <a href="javascript:window.open('https://s.apache.org/hadoop-2.8.1-announcement');" target="_blank" rel="noopener noreferrer">Apache Hadoop 2.8.1 <i class="fa fa-external-link"></i></a>, and <a href="javascript:window.open('https://s.apache.org/hadoop-2.9.0-announcement');" target="_blank" rel="noopener noreferrer">Apache Hadoop 2.9.0 <i class="fa fa-external-link"></i></a>.</p>
</div> </td>
</tr>
</tbody>
</table>
</div>
<div class="admonitionblock tip">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-tip" title="Tip"></i> </td>
<td class="content">
<div class="title">
Hadoop 3.0.x Releases
</div>
<div class="paragraph">
<p>Hadoop distributions that include the Application Timeline Service feature may cause unexpected versions of HBase classes to be present in the application classpath. Users planning on running MapReduce applications with HBase should make sure that <a href="javascript:window.open('https://issues.apache.org/jira/browse/YARN-7190');" target="_blank" rel="noopener noreferrer">YARN-7190 <i class="fa fa-external-link"></i></a> is present in their YARN service (currently fixed in 2.9.1+ and 3.1.0+).</p>
</div> </td>
</tr>
</tbody>
</table>
</div>
<div class="admonitionblock tip">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-tip" title="Tip"></i> </td>
<td class="content">
<div class="title">
Hadoop 3.1.0 Release
</div>
<div class="paragraph">
<p>The Hadoop PMC called out the 3.1.0 release as not stable / production ready. As such, HBase expressly advises downstream users to avoid running on top of this release. For reference, see the <a href="javascript:window.open('https://s.apache.org/hadoop-3.1.0-announcement');" target="_blank" rel="noopener noreferrer">release announcement for Hadoop 3.1.0 <i class="fa fa-external-link"></i></a>.</p>
</div> </td>
</tr>
</tbody>
</table>
</div>
<div class="admonitionblock note">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-note" title="Note"></i> </td>
<td class="content">
<div class="title">
Replace the Hadoop Bundled With HBase!
</div>
<div class="paragraph">
<p>Because HBase depends on Hadoop, it bundles Hadoop jars under its <em>lib</em> directory. The bundled jars are ONLY for use in standalone mode. In distributed mode, it is <em>critical</em> that the version of Hadoop that is out on your cluster match what is under HBase. Replace the hadoop jars found in the HBase lib directory with the equivalent hadoop jars from the version you are running on your cluster to avoid version mismatch issues. Make sure you replace the jars under HBase across your whole cluster. Hadoop version mismatch issues have various manifestations. Check for mismatch if HBase appears hung.</p>
</div> </td>
</tr>
</tbody>
</table>
</div>
<div class="sect3">
<h4 id="dfs.datanode.max.transfer.threads"><a class="anchor" href="#dfs.datanode.max.transfer.threads"></a>4.1.1. <code class="notranslate">dfs.datanode.max.transfer.threads</code> </h4>
<div class="paragraph">
<p>An HDFS DataNode has an upper bound on the number of files that it will serve at any one time. Before doing any loading, make sure you have configured Hadoop’s <em>conf/hdfs-site.xml</em>, setting the <code class="notranslate">dfs.datanode.max.transfer.threads</code> value to at least the following:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight notranslate"><code data-lang="xml"><span class="tag">&lt;property&gt;</span>
  <span class="tag">&lt;name&gt;</span>dfs.datanode.max.transfer.threads<span class="tag">&lt;/name&gt;</span>
  <span class="tag">&lt;value&gt;</span>4096<span class="tag">&lt;/value&gt;</span>
<span class="tag">&lt;/property&gt;</span></code></pre>
</div>
</div>
<div class="paragraph">
<p>Be sure to restart your HDFS after making the above configuration.</p>
</div>
<div class="paragraph">
<p>Not having this configuration in place makes for strange-looking failures. One manifestation is a complaint about missing blocks. For example:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">10/12/08 20:10:31 INFO hdfs.DFSClient: Could not obtain block
          blk_XXXXXXXXXXXXXXXXXXXXXX_YYYYYYYY from any node: java.io.IOException: No live nodes
          contain current block. Will get new block locations from namenode and retry...</pre>
</div>
</div>
<div class="paragraph">
<p>See also <a href="#casestudies.max.transfer.threads">casestudies.max.transfer.threads</a> and note that this property was previously known as <code class="notranslate">dfs.datanode.max.xcievers</code> (e.g. <a href="javascript:window.open('https://ccgtech.blogspot.com/2010/02/hadoop-hdfs-deceived-by-xciever.html');" target="_blank" rel="noopener noreferrer">Hadoop HDFS: Deceived by Xciever <i class="fa fa-external-link"></i></a>).</p>
</div>
</div>
</div>
<div class="sect2">
<h3 id="zookeeper.requirements"><a class="anchor" href="#zookeeper.requirements"></a>4.2. ZooKeeper Requirements</h3>
<div class="paragraph">
<p>ZooKeeper 3.4.x is required.</p>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="standalone_dist"><a class="anchor" href="#standalone_dist"></a>5. HBase run modes: Standalone and Distributed</h2>
<div class="sectionbody">
<div class="paragraph">
<p>HBase has two run modes: <a href="#standalone">standalone</a> and <a href="#distributed">distributed</a>. Out of the box, HBase runs in standalone mode. Whatever your mode, you will need to configure HBase by editing files in the HBase <em>conf</em> directory. At a minimum, you must edit <span class="code">conf/hbase-env.sh</span> to tell HBase which java to use. In this file you set HBase environment variables such as the heapsize and other options for the <code class="notranslate">JVM</code>, the preferred location for log files, etc. Set <span class="var">JAVA_HOME</span> to point at the root of your java install.</p>
</div>
<div class="sect2">
<h3 id="standalone"><a class="anchor" href="#standalone"></a>5.1. Standalone HBase</h3>
<div class="paragraph">
<p>This is the default mode. Standalone mode is what is described in the <a href="#quickstart">quickstart</a> section. In standalone mode, HBase does not use HDFS — it uses the local filesystem instead — and it runs all HBase daemons and a local ZooKeeper all up in the same JVM. ZooKeeper binds to a well known port so clients may talk to HBase.</p>
</div>
<div class="sect3">
<h4 id="standalone.over.hdfs"><a class="anchor" href="#standalone.over.hdfs"></a>5.1.1. Standalone HBase over HDFS</h4>
<div class="paragraph">
<p>A sometimes useful variation on standalone hbase has all daemons running inside the one JVM but rather than persist to the local filesystem, instead they persist to an HDFS instance.</p>
</div>
<div class="paragraph">
<p>You might consider this profile when you are intent on a simple deploy profile, the loading is light, but the data must persist across node comings and goings. Writing to HDFS where data is replicated ensures the latter.</p>
</div>
<div class="paragraph">
<p>To configure this standalone variant, edit your <em>hbase-site.xml</em> setting <em>hbase.rootdir</em> to point at a directory in your HDFS instance but then set <em>hbase.cluster.distributed</em> to <em>false</em>. For example:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight notranslate"><code data-lang="xml"><span class="tag">&lt;configuration&gt;</span>
  <span class="tag">&lt;property&gt;</span>
    <span class="tag">&lt;name&gt;</span>hbase.rootdir<span class="tag">&lt;/name&gt;</span>
    <span class="tag">&lt;value&gt;</span>hdfs://namenode.example.org:8020/hbase<span class="tag">&lt;/value&gt;</span>
  <span class="tag">&lt;/property&gt;</span>
  <span class="tag">&lt;property&gt;</span>
    <span class="tag">&lt;name&gt;</span>hbase.cluster.distributed<span class="tag">&lt;/name&gt;</span>
    <span class="tag">&lt;value&gt;</span>false<span class="tag">&lt;/value&gt;</span>
  <span class="tag">&lt;/property&gt;</span>
<span class="tag">&lt;/configuration&gt;</span></code></pre>
</div>
</div>
</div>
</div>
<div class="sect2">
<h3 id="distributed"><a class="anchor" href="#distributed"></a>5.2. Distributed</h3>
<div class="paragraph">
<p>Distributed mode can be subdivided into distributed but all daemons run on a single node — a.k.a. <em>pseudo-distributed</em> — and <em>fully-distributed</em> where the daemons are spread across all nodes in the cluster. The <em>pseudo-distributed</em> vs. <em>fully-distributed</em> nomenclature comes from Hadoop.</p>
</div>
<div class="paragraph">
<p>Pseudo-distributed mode can run against the local filesystem or it can run against an instance of the <em>Hadoop Distributed File System</em> (HDFS). Fully-distributed mode can ONLY run on HDFS. See the Hadoop <a href="javascript:window.open('https://hadoop.apache.org/docs/current/');" target="_blank" rel="noopener noreferrer">documentation <i class="fa fa-external-link"></i></a> for how to set up HDFS. A good walk-through for setting up HDFS on Hadoop 2 can be found at <a href="javascript:window.open('http://www.alexjf.net/blog/distributed-systems/hadoop-yarn-installation-definitive-guide');" class="bare" target="_blank" rel="noopener noreferrer">http://www.alexjf.net/blog/distributed-systems/hadoop-yarn-installation-definitive-guide <i class="fa fa-external-link"></i></a>.</p>
</div>
<div class="sect3">
<h4 id="pseudo"><a class="anchor" href="#pseudo"></a>5.2.1. Pseudo-distributed</h4>
<div class="admonitionblock note">
<table>
<tbody>
<tr>
<td class="icon"> <i class="fa icon-note" title="Note"></i> </td>
<td class="content">
<div class="title">
Pseudo-Distributed Quickstart
</div>
<div class="paragraph">
<p>A quickstart has been added to the <a href="#quickstart">quickstart</a> chapter. See <a href="#quickstart_pseudo">quickstart-pseudo</a>. Some of the information that was originally in this section has been moved there.</p>
</div> </td>
</tr>
</tbody>
</table>
</div>
<div class="paragraph">
<p>A pseudo-distributed mode is simply a fully-distributed mode run on a single host. Use this HBase configuration for testing and prototyping purposes only. Do not use this configuration for production or for performance evaluation.</p>
</div>
</div>
</div>
<div class="sect2">
<h3 id="fully_dist"><a class="anchor" href="#fully_dist"></a>5.3. Fully-distributed</h3>
<div class="paragraph">
<p>By default, HBase runs in standalone mode. Both standalone mode and pseudo-distributed mode are provided for the purposes of small-scale testing. For a production environment, distributed mode is advised. In distributed mode, multiple instances of HBase daemons run on multiple servers in the cluster.</p>
</div>
<div class="paragraph">
<p>Just as in pseudo-distributed mode, a fully distributed configuration requires that you set the <code class="notranslate">hbase.cluster.distributed</code> property to <code class="notranslate">true</code>. Typically, the <code class="notranslate">hbase.rootdir</code> is configured to point to a highly-available HDFS filesystem.</p>
</div>
<div class="paragraph">
<p>In addition, the cluster is configured so that multiple cluster nodes enlist as RegionServers, ZooKeeper QuorumPeers, and backup HMaster servers. These configuration basics are all demonstrated in <a href="#quickstart_fully_distributed">quickstart-fully-distributed</a>.</p>
</div>
<div class="paragraph">
<div class="title">
Distributed RegionServers
</div>
<p>Typically, your cluster will contain multiple RegionServers all running on different servers, as well as primary and backup Master and ZooKeeper daemons. The <em>conf/regionservers</em> file on the master server contains a list of hosts whose RegionServers are associated with this cluster. Each host is on a separate line. All hosts listed in this file will have their RegionServer processes started and stopped when the master server starts or stops.</p>
</div>
<div class="paragraph">
<div class="title">
ZooKeeper and HBase
</div>
<p>See the <a href="#zookeeper">ZooKeeper</a> section for ZooKeeper setup instructions for HBase.</p>
</div>
<div class="exampleblock">
<div class="title">
Example 3. Example Distributed HBase Cluster
</div>
<div class="content">
<div class="paragraph">
<p>This is a bare-bones <em>conf/hbase-site.xml</em> for a distributed HBase cluster. A cluster that is used for real-world work would contain more custom configuration parameters. Most HBase configuration directives have default values, which are used unless the value is overridden in the <em>hbase-site.xml</em>. See "<a href="#config.files">Configuration Files</a>" for more information.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight notranslate"><code data-lang="xml"><span class="tag">&lt;configuration&gt;</span>
  <span class="tag">&lt;property&gt;</span>
    <span class="tag">&lt;name&gt;</span>hbase.rootdir<span class="tag">&lt;/name&gt;</span>
    <span class="tag">&lt;value&gt;</span>hdfs://namenode.example.org:8020/hbase<span class="tag">&lt;/value&gt;</span>
  <span class="tag">&lt;/property&gt;</span>
  <span class="tag">&lt;property&gt;</span>
    <span class="tag">&lt;name&gt;</span>hbase.cluster.distributed<span class="tag">&lt;/name&gt;</span>
    <span class="tag">&lt;value&gt;</span>true<span class="tag">&lt;/value&gt;</span>
  <span class="tag">&lt;/property&gt;</span>
  <span class="tag">&lt;property&gt;</span>
    <span class="tag">&lt;name&gt;</span>hbase.zookeeper.quorum<span class="tag">&lt;/name&gt;</span>
    <span class="tag">&lt;value&gt;</span>node-a.example.com,node-b.example.com,node-c.example.com<span class="tag">&lt;/value&gt;</span>
  <span class="tag">&lt;/property&gt;</span>
<span class="tag">&lt;/configuration&gt;</span></code></pre>
</div>
</div>
<div class="paragraph">
<p>This is an example <em>conf/regionservers</em> file, which contains a list of nodes that should run a RegionServer in the cluster. These nodes need HBase installed and they need to use the same contents of the <em>conf/</em> directory as the Master server</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight notranslate"><code data-lang="java">node-a.example.com
node-b.example.com
node-c.example.com</code></pre>
</div>
</div>
<div class="paragraph">
<p>This is an example <em>conf/backup-masters</em> file, which contains a list of each node that should run a backup Master instance. The backup Master instances will sit idle unless the main Master becomes unavailable.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight notranslate"><code data-lang="java">node-b.example.com
node-c.example.com</code></pre>
</div>
</div>
</div>
</div>
<div class="paragraph">
<div class="title">
Distributed HBase Quickstart
</div>
<p>See <a href="#quickstart_fully_distributed">quickstart-fully-distributed</a> for a walk-through of a simple three-node cluster configuration with multiple ZooKeeper, backup HMaster, and RegionServer instances.</p>
</div>
<div class="olist arabic">
<div class="title">
Procedure: HDFS Client Configuration
</div>
<ol class="arabic">
<li> <p>Of note, if you have made HDFS client configuration changes on your Hadoop cluster, such as configuration directives for HDFS clients, as opposed to server-side configurations, you must use one of the following methods to enable HBase to see and use these configuration changes:</p>
<div class="olist loweralpha">
<ol class="loweralpha" type="a">
<li> <p>Add a pointer to your <code class="notranslate">HADOOP_CONF_DIR</code> to the <code class="notranslate">HBASE_CLASSPATH</code> environment variable in <em>hbase-env.sh</em>.</p> </li>
<li> <p>Add a copy of <em>hdfs-site.xml</em> (or <em>hadoop-site.xml</em>) or, better, symlinks, under <em>${HBASE_HOME}/conf</em>, or</p> </li>
<li> <p>if only a small set of HDFS client configurations, add them to <em>hbase-site.xml</em>.</p> </li>
</ol>
</div> </li>
</ol>
</div>
<div class="paragraph">
<p>An example of such an HDFS client configuration is <code class="notranslate">dfs.replication</code>. If for example, you want to run with a replication factor of 5, HBase will create files with the default of 3 unless you do the above to make the configuration available to HBase.</p>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="confirm"><a class="anchor" href="#confirm"></a>6. Running and Confirming Your Installation</h2>
<div class="sectionbody">
<div class="paragraph">
<p>Make sure HDFS is running first. Start and stop the Hadoop HDFS daemons by running <em>bin/start-hdfs.sh</em> over in the <code class="notranslate">HADOOP_HOME</code> directory. You can ensure it started properly by testing the <code class="notranslate">put</code> and <code class="notranslate">get</code> of files into the Hadoop filesystem. HBase does not normally use the MapReduce or YARN daemons. These do not need to be started.</p>
</div>
<div class="paragraph">
<p><em>If</em> you are managing your own ZooKeeper, start it and confirm it’s running, else HBase will start up ZooKeeper for you as part of its start process.</p>
</div>
<div class="paragraph">
<p>Start HBase with the following command:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">bin/start-hbase.sh</pre>
</div>
</div>
<div class="paragraph">
<p>Run the above from the <code class="notranslate">HBASE_HOME</code> directory.</p>
</div>
<div class="paragraph">
<p>You should now have a running HBase instance. HBase logs can be found in the <em>logs</em> subdirectory. Check them out especially if HBase had trouble starting.</p>
</div>
<div class="paragraph">
<p>HBase also puts up a UI listing vital attributes. By default it’s deployed on the Master host at port 16010 (HBase RegionServers listen on port 16020 by default and put up an informational HTTP server at port 16030). If the Master is running on a host named <code class="notranslate">master.example.org</code> on the default port, point your browser at http://master.example.org:16010 to see the web interface.</p>
</div>
<div class="paragraph">
<p>Once HBase has started, see the <a href="#shell_exercises">shell exercises</a> section for how to create tables, add data, scan your insertions, and finally disable and drop your tables.</p>
</div>
<div class="paragraph">
<p>To stop HBase after exiting the HBase shell enter</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="notranslate">$ ./bin/stop-hbase.sh
stopping hbase...............</pre>
</div>
</div>
<div class="paragraph">
<p>Shutdown can take a moment to complete. It can take longer if your cluster is comprised of many machines. If you are running a distributed operation, be sure to wait until HBase has shut down completely before stopping the Hadoop daemons.</p>
</div>
</div>
</div>
<div class="sect1">
<h2 id="config.files"><a class="anchor" href="#config.files"></a>7. Default Configuration</h2>
<div class="sectionbody">
<div class="sect2">
<h3 id="hbase.site"><a class="anchor" href="#hbase.site"></a>7.1. <em>hbase-site.xml</em> and <em>hbase-default.xml</em></h3>
<div class="paragraph">
<p>Just as in Hadoop where you add site-specific HDFS configuration to the <em>hdfs-site.xml</em> file, for HBase, site specific customizations go into the file <em>conf/hbase-site.xml</em>. For the list of configurable properties, see <a href="#hbase_default_configurations">hbase default configurations</a> below or view the raw <em>hbase-default.xml</em> source file in the HBase source code at <em>src/main/resources</em>.</p>
</div>
<div class="paragraph">
<p>Not all configuration options make it out to <em>hbase-default.xml</em>. Some configurations would only appear in source code; the only way to identify these changes are through code review.</p>
</div>
<div class="paragraph">
<p>Currently, changes here will require a cluster restart for HBase to notice the change.</p>
</div>
</div>
<div class="sect2">
<h3 id="hbase_default_configurations"><a class="anchor" href="#hbase_default_configurations"></a>7.2. HBase Default Configuration</h3>
<div class="paragraph">
<p>The documentation below is generated using the default hbase configuration file, <em>hbase-default.xml</em>, as source.</p>
</div>
<div id="hbase.tmp.dir" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.tmp.dir</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Temporary directory on the local filesystem. Change this setting to point to a location more permanent than '/tmp', the usual resolve for java.io.tmpdir, as the '/tmp' directory is cleared on machine restart.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">${java.io.tmpdir}/hbase-${user.name}</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.rootdir" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.rootdir</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The directory shared by region servers and into which HBase persists. The URL should be 'fully-qualified' to include the filesystem scheme. For example, to specify the HDFS directory '/hbase' where the HDFS instance’s namenode is running at namenode.example.org on port 9000, set this value to: hdfs://namenode.example.org:9000/hbase. By default, we write to whatever ${hbase.tmp.dir} is set too — usually /tmp — so change this configuration or else all data will be lost on machine restart.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">${hbase.tmp.dir}/hbase</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.cluster.distributed" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.cluster.distributed</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The mode the cluster will be in. Possible values are false for standalone mode and true for distributed mode. If false, startup will run all HBase and ZooKeeper daemons together in the one JVM.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">false</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.zookeeper.quorum" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.zookeeper.quorum</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Comma separated list of servers in the ZooKeeper ensemble (This config. should have been named hbase.zookeeper.ensemble). For example, "host1.mydomain.com,host2.mydomain.com,host3.mydomain.com". By default this is set to localhost for local and pseudo-distributed modes of operation. For a fully-distributed setup, this should be set to a full list of ZooKeeper ensemble servers. If HBASE_MANAGES_ZK is set in hbase-env.sh this is the list of servers which hbase will start/stop ZooKeeper on as part of cluster start/stop. Client-side, we will take this list of ensemble members and put it together with the hbase.zookeeper.property.clientPort config. and pass it into zookeeper constructor as the connectString parameter.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">localhost</code></p>
</div>
</dd>
</dl>
</div>
<div id="zookeeper.recovery.retry.maxsleeptime" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">zookeeper.recovery.retry.maxsleeptime</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Max sleep time before retry zookeeper operations in milliseconds, a max time is needed here so that sleep time won’t grow unboundedly</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">60000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.local.dir" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.local.dir</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Directory on the local filesystem to be used as a local storage.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">${hbase.tmp.dir}/local/</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.master.port" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.master.port</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The port the HBase Master should bind to.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">16000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.master.info.port" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.master.info.port</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The port for the HBase Master web UI. Set to -1 if you do not want a UI instance run.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">16010</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.master.info.bindAddress" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.master.info.bindAddress</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The bind address for the HBase Master web UI</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">0.0.0.0</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.master.logcleaner.plugins" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.master.logcleaner.plugins</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>A comma-separated list of BaseLogCleanerDelegate invoked by the LogsCleaner service. These WAL cleaners are called in order, so put the cleaner that prunes the most files in front. To implement your own BaseLogCleanerDelegate, just put it in HBase’s classpath and add the fully qualified class name here. Always add the above default log cleaners in the list.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">org.apache.hadoop.hbase.master.cleaner.TimeToLiveLogCleaner,org.apache.hadoop.hbase.master.cleaner.TimeToLiveProcedureWALCleaner</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.master.logcleaner.ttl" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.master.logcleaner.ttl</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>How long a WAL remain in the archive ({hbase.rootdir}/oldWALs) directory, after which it will be cleaned by a Master thread. The value is in milliseconds.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">600000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.master.procedurewalcleaner.ttl" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.master.procedurewalcleaner.ttl</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>How long a Procedure WAL will remain in the archive directory, after which it will be cleaned by a Master thread. The value is in milliseconds.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">604800000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.master.hfilecleaner.plugins" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.master.hfilecleaner.plugins</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>A comma-separated list of BaseHFileCleanerDelegate invoked by the HFileCleaner service. These HFiles cleaners are called in order, so put the cleaner that prunes the most files in front. To implement your own BaseHFileCleanerDelegate, just put it in HBase’s classpath and add the fully qualified class name here. Always add the above default log cleaners in the list as they will be overwritten in hbase-site.xml.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">org.apache.hadoop.hbase.master.cleaner.TimeToLiveHFileCleaner</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.master.infoserver.redirect" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.master.infoserver.redirect</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Whether or not the Master listens to the Master web UI port (hbase.master.info.port) and redirects requests to the web UI server shared by the Master and RegionServer. Config. makes sense when Master is serving Regions (not the default).</p>
 </div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">true</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.master.fileSplitTimeout" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.master.fileSplitTimeout</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Splitting a region, how long to wait on the file-splitting step before aborting the attempt. Default: 600000. This setting used to be known as hbase.regionserver.fileSplitTimeout in hbase-1.x. Split is now run master-side hence the rename (If a 'hbase.master.fileSplitTimeout' setting found, will use it to prime the current 'hbase.master.fileSplitTimeout' Configuration.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">600000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.port" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.port</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The port the HBase RegionServer binds to.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">16020</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.info.port" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.info.port</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The port for the HBase RegionServer web UI Set to -1 if you do not want the RegionServer UI to run.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">16030</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.info.bindAddress" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.info.bindAddress</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The address for the HBase RegionServer web UI</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">0.0.0.0</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.info.port.auto" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.info.port.auto</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Whether or not the Master or RegionServer UI should search for a port to bind to. Enables automatic port search if hbase.regionserver.info.port is already in use. Useful for testing, turned off by default.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">false</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.handler.count" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.handler.count</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Count of RPC Listener instances spun up on RegionServers. Same property is used by the Master for count of master handlers. Too many handlers can be counter-productive. Make it a multiple of CPU count. If mostly read-only, handlers count close to cpu count does well. Start with twice the CPU count and tune from there.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">30</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.ipc.server.callqueue.handler.factor" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.ipc.server.callqueue.handler.factor</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Factor to determine the number of call queues. A value of 0 means a single queue shared between all the handlers. A value of 1 means that each handler has its own queue.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">0.1</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.ipc.server.callqueue.read.ratio" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.ipc.server.callqueue.read.ratio</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Split the call queues into read and write queues. The specified interval (which should be between 0.0 and 1.0) will be multiplied by the number of call queues. A value of 0 indicate to not split the call queues, meaning that both read and write requests will be pushed to the same set of queues. A value lower than 0.5 means that there will be less read queues than write queues. A value of 0.5 means there will be the same number of read and write queues. A value greater than 0.5 means that there will be more read queues than write queues. A value of 1.0 means that all the queues except one are used to dispatch read requests. Example: Given the total number of call queues being 10 a read.ratio of 0 means that: the 10 queues will contain both read/write requests. a read.ratio of 0.3 means that: 3 queues will contain only read requests and 7 queues will contain only write requests. a read.ratio of 0.5 means that: 5 queues will contain only read requests and 5 queues will contain only write requests. a read.ratio of 0.8 means that: 8 queues will contain only read requests and 2 queues will contain only write requests. a read.ratio of 1 means that: 9 queues will contain only read requests and 1 queues will contain only write requests.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">0</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.ipc.server.callqueue.scan.ratio" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.ipc.server.callqueue.scan.ratio</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Given the number of read call queues, calculated from the total number of call queues multiplied by the callqueue.read.ratio, the scan.ratio property will split the read call queues into small-read and long-read queues. A value lower than 0.5 means that there will be less long-read queues than short-read queues. A value of 0.5 means that there will be the same number of short-read and long-read queues. A value greater than 0.5 means that there will be more long-read queues than short-read queues A value of 0 or 1 indicate to use the same set of queues for gets and scans. Example: Given the total number of read call queues being 8 a scan.ratio of 0 or 1 means that: 8 queues will contain both long and short read requests. a scan.ratio of 0.3 means that: 2 queues will contain only long-read requests and 6 queues will contain only short-read requests. a scan.ratio of 0.5 means that: 4 queues will contain only long-read requests and 4 queues will contain only short-read requests. a scan.ratio of 0.8 means that: 6 queues will contain only long-read requests and 2 queues will contain only short-read requests.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">0</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.msginterval" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.msginterval</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Interval between messages from the RegionServer to Master in milliseconds.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">3000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.logroll.period" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.logroll.period</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Period at which we will roll the commit log regardless of how many edits it has.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">3600000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.logroll.errors.tolerated" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.logroll.errors.tolerated</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The number of consecutive WAL close errors we will allow before triggering a server abort. A setting of 0 will cause the region server to abort if closing the current WAL writer fails during log rolling. Even a small value (2 or 3) will allow a region server to ride over transient HDFS errors.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">2</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.hlog.reader.impl" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.hlog.reader.impl</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The WAL file reader implementation.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">org.apache.hadoop.hbase.regionserver.wal.ProtobufLogReader</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.hlog.writer.impl" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.hlog.writer.impl</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The WAL file writer implementation.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">org.apache.hadoop.hbase.regionserver.wal.ProtobufLogWriter</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.global.memstore.size" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.global.memstore.size</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Maximum size of all memstores in a region server before new updates are blocked and flushes are forced. Defaults to 40% of heap (0.4). Updates are blocked and flushes are forced until size of all memstores in a region server hits hbase.regionserver.global.memstore.size.lower.limit. The default value in this configuration has been intentionally left empty in order to honor the old hbase.regionserver.global.memstore.upperLimit property if present.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p>none</p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.global.memstore.size.lower.limit" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.global.memstore.size.lower.limit</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Maximum size of all memstores in a region server before flushes are forced. Defaults to 95% of hbase.regionserver.global.memstore.size (0.95). A 100% value for this value causes the minimum possible flushing to occur when updates are blocked due to memstore limiting. The default value in this configuration has been intentionally left empty in order to honor the old hbase.regionserver.global.memstore.lowerLimit property if present.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p>none</p>
</div>
</dd>
</dl>
</div>
<div id="hbase.systemtables.compacting.memstore.type" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.systemtables.compacting.memstore.type</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Determines the type of memstore to be used for system tables like META, namespace tables etc. By default NONE is the type and hence we use the default memstore for all the system tables. If we need to use compacting memstore for system tables then set this property to BASIC/EAGER</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">NONE</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.optionalcacheflushinterval" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.optionalcacheflushinterval</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Maximum amount of time an edit lives in memory before being automatically flushed. Default 1 hour. Set it to 0 to disable automatic flushing.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">3600000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.dns.interface" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.dns.interface</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The name of the Network Interface from which a region server should report its IP address.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">default</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.dns.nameserver" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.dns.nameserver</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The host name or IP address of the name server (DNS) which a region server should use to determine the host name used by the master for communication and display purposes.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">default</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.region.split.policy" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.region.split.policy</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>A split policy determines when a region should be split. The various other split policies that are available currently are BusyRegionSplitPolicy, ConstantSizeRegionSplitPolicy, DisabledRegionSplitPolicy, DelimitedKeyPrefixRegionSplitPolicy, KeyPrefixRegionSplitPolicy, and SteppingSplitPolicy. DisabledRegionSplitPolicy blocks manual region splitting.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">org.apache.hadoop.hbase.regionserver.SteppingSplitPolicy</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.regionSplitLimit" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.regionSplitLimit</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Limit for the number of regions after which no more region splitting should take place. This is not hard limit for the number of regions but acts as a guideline for the regionserver to stop splitting after a certain limit. Default is set to 1000.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">1000</code></p>
</div>
</dd>
</dl>
</div>
<div id="zookeeper.session.timeout" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">zookeeper.session.timeout</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>ZooKeeper session timeout in milliseconds. It is used in two different ways. First, this value is used in the ZK client that HBase uses to connect to the ensemble. It is also used by HBase when it starts a ZK server and it is passed as the 'maxSessionTimeout'. See <a href="javascript:window.open('https://zookeeper.apache.org/doc/current/zookeeperProgrammers.html#ch_zkSessions');" class="bare" target="_blank" rel="noopener noreferrer">https://zookeeper.apache.org/doc/current/zookeeperProgrammers.html#ch_zkSessions <i class="fa fa-external-link"></i></a>. For example, if an HBase region server connects to a ZK ensemble that’s also managed by HBase, then the session timeout will be the one specified by this configuration. But, a region server that connects to an ensemble managed with a different configuration will be subjected that ensemble’s maxSessionTimeout. So, even though HBase might propose using 90 seconds, the ensemble can have a max timeout lower than this and it will take precedence. The current default maxSessionTimeout that ZK ships with is 40 seconds, which is lower than HBase’s.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">90000</code></p>
</div>
</dd>
</dl>
</div>
<div id="zookeeper.znode.parent" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">zookeeper.znode.parent</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Root ZNode for HBase in ZooKeeper. All of HBase’s ZooKeeper files that are configured with a relative path will go under this node. By default, all of HBase’s ZooKeeper file paths are configured with a relative path, so they will all go under this directory unless changed.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">/hbase</code></p>
</div>
</dd>
</dl>
</div>
<div id="zookeeper.znode.acl.parent" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">zookeeper.znode.acl.parent</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Root ZNode for access control lists.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">acl</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.zookeeper.dns.interface" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.zookeeper.dns.interface</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The name of the Network Interface from which a ZooKeeper server should report its IP address.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">default</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.zookeeper.dns.nameserver" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.zookeeper.dns.nameserver</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The host name or IP address of the name server (DNS) which a ZooKeeper server should use to determine the host name used by the master for communication and display purposes.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">default</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.zookeeper.peerport" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.zookeeper.peerport</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Port used by ZooKeeper peers to talk to each other. See <a href="javascript:window.open('https://zookeeper.apache.org/doc/r3.3.3/zookeeperStarted.html#sc_RunningReplicatedZooKeeper');" class="bare" target="_blank" rel="noopener noreferrer">https://zookeeper.apache.org/doc/r3.3.3/zookeeperStarted.html#sc_RunningReplicatedZooKeeper <i class="fa fa-external-link"></i></a> for more information.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">2888</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.zookeeper.leaderport" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.zookeeper.leaderport</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Port used by ZooKeeper for leader election. See <a href="javascript:window.open('https://zookeeper.apache.org/doc/r3.3.3/zookeeperStarted.html#sc_RunningReplicatedZooKeeper');" class="bare" target="_blank" rel="noopener noreferrer">https://zookeeper.apache.org/doc/r3.3.3/zookeeperStarted.html#sc_RunningReplicatedZooKeeper <i class="fa fa-external-link"></i></a> for more information.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">3888</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.zookeeper.property.initLimit" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.zookeeper.property.initLimit</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Property from ZooKeeper’s config zoo.cfg. The number of ticks that the initial synchronization phase can take.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">10</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.zookeeper.property.syncLimit" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.zookeeper.property.syncLimit</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Property from ZooKeeper’s config zoo.cfg. The number of ticks that can pass between sending a request and getting an acknowledgment.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">5</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.zookeeper.property.dataDir" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.zookeeper.property.dataDir</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Property from ZooKeeper’s config zoo.cfg. The directory where the snapshot is stored.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">${hbase.tmp.dir}/zookeeper</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.zookeeper.property.clientPort" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.zookeeper.property.clientPort</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Property from ZooKeeper’s config zoo.cfg. The port at which the clients will connect.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">2181</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.zookeeper.property.maxClientCnxns" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.zookeeper.property.maxClientCnxns</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Property from ZooKeeper’s config zoo.cfg. Limit on number of concurrent connections (at the socket level) that a single client, identified by IP address, may make to a single member of the ZooKeeper ensemble. Set high to avoid zk connection issues running standalone and pseudo-distributed.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">300</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.client.write.buffer" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.client.write.buffer</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Default size of the BufferedMutator write buffer in bytes. A bigger buffer takes more memory — on both the client and server side since server instantiates the passed write buffer to process it — but a larger buffer size reduces the number of RPCs made. For an estimate of server-side memory-used, evaluate hbase.client.write.buffer * hbase.regionserver.handler.count</p>
</div>
 <div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">2097152</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.client.pause" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.client.pause</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>General client pause value. Used mostly as value to wait before running a retry of a failed get, region lookup, etc. See hbase.client.retries.number for description of how we backoff from this initial pause amount and how this pause works w/ retries.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">100</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.client.pause.cqtbe" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.client.pause.cqtbe</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Whether or not to use a special client pause for CallQueueTooBigException (cqtbe). Set this property to a higher value than hbase.client.pause if you observe frequent CQTBE from the same RegionServer and the call queue there keeps full</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p>none</p>
</div>
</dd>
</dl>
</div>
<div id="hbase.client.retries.number" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.client.retries.number</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Maximum retries. Used as maximum for all retryable operations such as the getting of a cell’s value, starting a row update, etc. Retry interval is a rough function based on hbase.client.pause. At first we retry at this interval but then with backoff, we pretty quickly reach retrying every ten seconds. See HConstants#RETRY_BACKOFF for how the backup ramps up. Change this setting and hbase.client.pause to suit your workload.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">15</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.client.max.total.tasks" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.client.max.total.tasks</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The maximum number of concurrent mutation tasks a single HTable instance will send to the cluster.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">100</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.client.max.perserver.tasks" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.client.max.perserver.tasks</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The maximum number of concurrent mutation tasks a single HTable instance will send to a single region server.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">2</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.client.max.perregion.tasks" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.client.max.perregion.tasks</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The maximum number of concurrent mutation tasks the client will maintain to a single Region. That is, if there is already hbase.client.max.perregion.tasks writes in progress for this region, new puts won’t be sent to this region until some writes finishes.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">1</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.client.perserver.requests.threshold" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.client.perserver.requests.threshold</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The max number of concurrent pending requests for one server in all client threads (process level). Exceeding requests will be thrown ServerTooBusyException immediately to prevent user’s threads being occupied and blocked by only one slow region server. If you use a fix number of threads to access HBase in a synchronous way, set this to a suitable value which is related to the number of threads will help you. See <a href="javascript:window.open('https://issues.apache.org/jira/browse/HBASE-16388');" class="bare" target="_blank" rel="noopener noreferrer">https://issues.apache.org/jira/browse/HBASE-16388 <i class="fa fa-external-link"></i></a> for details.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">2147483647</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.client.scanner.caching" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.client.scanner.caching</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Number of rows that we try to fetch when calling next on a scanner if it is not served from (local, client) memory. This configuration works together with hbase.client.scanner.max.result.size to try and use the network efficiently. The default value is Integer.MAX_VALUE by default so that the network will fill the chunk size defined by hbase.client.scanner.max.result.size rather than be limited by a particular number of rows since the size of rows varies table to table. If you know ahead of time that you will not require more than a certain number of rows from a scan, this configuration should be set to that row limit via Scan#setCaching. Higher caching values will enable faster scanners but will eat up more memory and some calls of next may take longer and longer times when the cache is empty. Do not set this value such that the time between invocations is greater than the scanner timeout; i.e. hbase.client.scanner.timeout.period</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">2147483647</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.client.keyvalue.maxsize" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.client.keyvalue.maxsize</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Specifies the combined maximum allowed size of a KeyValue instance. This is to set an upper boundary for a single entry saved in a storage file. Since they cannot be split it helps avoiding that a region cannot be split any further because the data is too large. It seems wise to set this to a fraction of the maximum region size. Setting it to zero or less disables the check.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">10485760</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.server.keyvalue.maxsize" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.server.keyvalue.maxsize</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Maximum allowed size of an individual cell, inclusive of value and all key components. A value of 0 or less disables the check. The default value is 10MB. This is a safety setting to protect the server from OOM situations.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">10485760</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.client.scanner.timeout.period" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.client.scanner.timeout.period</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Client scanner lease period in milliseconds.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">60000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.client.localityCheck.threadPoolSize" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.client.localityCheck.threadPoolSize</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">2</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.bulkload.retries.number" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.bulkload.retries.number</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Maximum retries. This is maximum number of iterations to atomic bulk loads are attempted in the face of splitting operations 0 means never give up.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">10</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.master.balancer.maxRitPercent" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.master.balancer.maxRitPercent</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The max percent of regions in transition when balancing. The default value is 1.0. So there are no balancer throttling. If set this config to 0.01, It means that there are at most 1% regions in transition when balancing. Then the cluster’s availability is at least 99% when balancing.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">1.0</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.balancer.period" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.balancer.period</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Period at which the region balancer runs in the Master.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">300000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.normalizer.period" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.normalizer.period</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Period at which the region normalizer runs in the Master.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">300000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regions.slop" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regions.slop</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Rebalance if any regionserver has average + (average * slop) regions. The default value of this parameter is 0.001 in StochasticLoadBalancer (the default load balancer), while the default is 0.2 in other load balancers (i.e., SimpleLoadBalancer).</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">0.001</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.server.thread.wakefrequency" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.server.thread.wakefrequency</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Time to sleep in between searches for work (in milliseconds). Used as sleep interval by service threads such as log roller.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">10000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.server.versionfile.writeattempts" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.server.versionfile.writeattempts</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>How many times to retry attempting to write a version file before just aborting. Each attempt is separated by the hbase.server.thread.wakefrequency milliseconds.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">3</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hregion.memstore.flush.size" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hregion.memstore.flush.size</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Memstore will be flushed to disk if size of the memstore exceeds this number of bytes. Value is checked by a thread that runs every hbase.server.thread.wakefrequency.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">134217728</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hregion.percolumnfamilyflush.size.lower.bound.min" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hregion.percolumnfamilyflush.size.lower.bound.min</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>If FlushLargeStoresPolicy is used and there are multiple column families, then every time that we hit the total memstore limit, we find out all the column families whose memstores exceed a "lower bound" and only flush them while retaining the others in memory. The "lower bound" will be "hbase.hregion.memstore.flush.size / column_family_number" by default unless value of this property is larger than that. If none of the families have their memstore size more than lower bound, all the memstores will be flushed (just as usual).</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">16777216</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hregion.preclose.flush.size" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hregion.preclose.flush.size</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>If the memstores in a region are this size or larger when we go to close, run a "pre-flush" to clear out memstores before we put up the region closed flag and take the region offline. On close, a flush is run under the close flag to empty memory. During this time the region is offline and we are not taking on any writes. If the memstore content is large, this flush could take a long time to complete. The preflush is meant to clean out the bulk of the memstore before putting up the close flag and taking the region offline so the flush that runs under the close flag has little to do.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">5242880</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hregion.memstore.block.multiplier" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hregion.memstore.block.multiplier</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Block updates if memstore has hbase.hregion.memstore.block.multiplier times hbase.hregion.memstore.flush.size bytes. Useful preventing runaway memstore during spikes in update traffic. Without an upper-bound, memstore fills such that when it flushes the resultant flush files take a long time to compact or split, or worse, we OOME.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">4</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hregion.memstore.mslab.enabled" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hregion.memstore.mslab.enabled</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Enables the MemStore-Local Allocation Buffer, a feature which works to prevent heap fragmentation under heavy write loads. This can reduce the frequency of stop-the-world GC pauses on large heaps.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">true</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hregion.max.filesize" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hregion.max.filesize</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Maximum HFile size. If the sum of the sizes of a region’s HFiles has grown to exceed this value, the region is split in two.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">10737418240</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hregion.majorcompaction" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hregion.majorcompaction</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Time between major compactions, expressed in milliseconds. Set to 0 to disable time-based automatic major compactions. User-requested and size-based major compactions will still run. This value is multiplied by hbase.hregion.majorcompaction.jitter to cause compaction to start at a somewhat-random time during a given window of time. The default value is 7 days, expressed in milliseconds. If major compactions are causing disruption in your environment, you can configure them to run at off-peak times for your deployment, or disable time-based major compactions by setting this parameter to 0, and run major compactions in a cron job or by another external mechanism.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">604800000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hregion.majorcompaction.jitter" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hregion.majorcompaction.jitter</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>A multiplier applied to hbase.hregion.majorcompaction to cause compaction to occur a given amount of time either side of hbase.hregion.majorcompaction. The smaller the number, the closer the compactions will happen to the hbase.hregion.majorcompaction interval.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">0.50</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hstore.compactionThreshold" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hstore.compactionThreshold</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>If more than this number of StoreFiles exist in any one Store (one StoreFile is written per flush of MemStore), a compaction is run to rewrite all StoreFiles into a single StoreFile. Larger values delay compaction, but when compaction does occur, it takes longer to complete.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">3</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hstore.flusher.count" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hstore.flusher.count</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The number of flush threads. With fewer threads, the MemStore flushes will be queued. With more threads, the flushes will be executed in parallel, increasing the load on HDFS, and potentially causing more compactions.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">2</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hstore.blockingStoreFiles" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hstore.blockingStoreFiles</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>If more than this number of StoreFiles exist in any one Store (one StoreFile is written per flush of MemStore), updates are blocked for this region until a compaction is completed, or until hbase.hstore.blockingWaitTime has been exceeded.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">16</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hstore.blockingWaitTime" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hstore.blockingWaitTime</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The time for which a region will block updates after reaching the StoreFile limit defined by hbase.hstore.blockingStoreFiles. After this time has elapsed, the region will stop blocking updates even if a compaction has not been completed.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">90000</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hstore.compaction.min" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hstore.compaction.min</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The minimum number of StoreFiles which must be eligible for compaction before compaction can run. The goal of tuning hbase.hstore.compaction.min is to avoid ending up with too many tiny StoreFiles to compact. Setting this value to 2 would cause a minor compaction each time you have two StoreFiles in a Store, and this is probably not appropriate. If you set this value too high, all the other values will need to be adjusted accordingly. For most cases, the default value is appropriate. In previous versions of HBase, the parameter hbase.hstore.compaction.min was named hbase.hstore.compactionThreshold.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">3</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hstore.compaction.max" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hstore.compaction.max</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The maximum number of StoreFiles which will be selected for a single minor compaction, regardless of the number of eligible StoreFiles. Effectively, the value of hbase.hstore.compaction.max controls the length of time it takes a single compaction to complete. Setting it larger means that more StoreFiles are included in a compaction. For most cases, the default value is appropriate.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">10</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hstore.compaction.min.size" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hstore.compaction.min.size</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>A StoreFile (or a selection of StoreFiles, when using ExploringCompactionPolicy) smaller than this size will always be eligible for minor compaction. HFiles this size or larger are evaluated by hbase.hstore.compaction.ratio to determine if they are eligible. Because this limit represents the "automatic include" limit for all StoreFiles smaller than this value, this value may need to be reduced in write-heavy environments where many StoreFiles in the 1-2 MB range are being flushed, because every StoreFile will be targeted for compaction and the resulting StoreFiles may still be under the minimum size and require further compaction. If this parameter is lowered, the ratio check is triggered more quickly. This addressed some issues seen in earlier versions of HBase but changing this parameter is no longer necessary in most situations. Default: 128 MB expressed in bytes.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">134217728</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hstore.compaction.max.size" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hstore.compaction.max.size</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>A StoreFile (or a selection of StoreFiles, when using ExploringCompactionPolicy) larger than this size will be excluded from compaction. The effect of raising hbase.hstore.compaction.max.size is fewer, larger StoreFiles that do not get compacted often. If you feel that compaction is happening too often without much benefit, you can try raising this value. Default: the value of LONG.MAX_VALUE, expressed in bytes.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">9223372036854775807</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hstore.compaction.ratio" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hstore.compaction.ratio</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>For minor compaction, this ratio is used to determine whether a given StoreFile which is larger than hbase.hstore.compaction.min.size is eligible for compaction. Its effect is to limit compaction of large StoreFiles. The value of hbase.hstore.compaction.ratio is expressed as a floating-point decimal. A large ratio, such as 10, will produce a single giant StoreFile. Conversely, a low value, such as .25, will produce behavior similar to the BigTable compaction algorithm, producing four StoreFiles. A moderate value of between 1.0 and 1.4 is recommended. When tuning this value, you are balancing write costs with read costs. Raising the value (to something like 1.4) will have more write costs, because you will compact larger StoreFiles. However, during reads, HBase will need to seek through fewer StoreFiles to accomplish the read. Consider this approach if you cannot take advantage of Bloom filters. Otherwise, you can lower this value to something like 1.0 to reduce the background cost of writes, and use Bloom filters to control the number of StoreFiles touched during reads. For most cases, the default value is appropriate.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">1.2F</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hstore.compaction.ratio.offpeak" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hstore.compaction.ratio.offpeak</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Allows you to set a different (by default, more aggressive) ratio for determining whether larger StoreFiles are included in compactions during off-peak hours. Works in the same way as hbase.hstore.compaction.ratio. Only applies if hbase.offpeak.start.hour and hbase.offpeak.end.hour are also enabled.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">5.0F</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hstore.time.to.purge.deletes" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hstore.time.to.purge.deletes</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The amount of time to delay purging of delete markers with future timestamps. If unset, or set to 0, all delete markers, including those with future timestamps, are purged during the next major compaction. Otherwise, a delete marker is kept until the major compaction which occurs after the marker’s timestamp plus the value of this setting, in milliseconds.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">0</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.offpeak.start.hour" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.offpeak.start.hour</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The start of off-peak hours, expressed as an integer between 0 and 23, inclusive. Set to -1 to disable off-peak.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">-1</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.offpeak.end.hour" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.offpeak.end.hour</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The end of off-peak hours, expressed as an integer between 0 and 23, inclusive. Set to -1 to disable off-peak.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">-1</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.thread.compaction.throttle" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.thread.compaction.throttle</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>There are two different thread pools for compactions, one for large compactions and the other for small compactions. This helps to keep compaction of lean tables (such as hbase:meta) fast. If a compaction is larger than this threshold, it goes into the large compaction pool. In most cases, the default value is appropriate. Default: 2 x hbase.hstore.compaction.max x hbase.hregion.memstore.flush.size (which defaults to 128MB). The value field assumes that the value of hbase.hregion.memstore.flush.size is unchanged from the default.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">2684354560</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.majorcompaction.pagecache.drop" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.majorcompaction.pagecache.drop</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Specifies whether to drop pages read/written into the system page cache by major compactions. Setting it to true helps prevent major compactions from polluting the page cache, which is almost always required, especially for clusters with low/moderate memory to storage ratio.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">true</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.regionserver.minorcompaction.pagecache.drop" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.regionserver.minorcompaction.pagecache.drop</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Specifies whether to drop pages read/written into the system page cache by minor compactions. Setting it to true helps prevent minor compactions from polluting the page cache, which is most beneficial on clusters with low memory to storage ratio or very write heavy clusters. You may want to set it to false under moderate to low write workload when bulk of the reads are on the most recently written data.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">true</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.hstore.compaction.kv.max" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.hstore.compaction.kv.max</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The maximum number of KeyValues to read and then write in a batch when flushing or compacting. Set this lower if you have big KeyValues and problems with Out Of Memory Exceptions Set this higher if you have wide, small rows.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">10</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.storescanner.parallel.seek.enable" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.storescanner.parallel.seek.enable</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Enables StoreFileScanner parallel-seeking in StoreScanner, a feature which can reduce response latency under special conditions.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">false</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.storescanner.parallel.seek.threads" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.storescanner.parallel.seek.threads</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>The default thread pool size if parallel-seeking feature enabled.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">10</code></p>
</div>
</dd>
</dl>
</div>
<div id="hfile.block.cache.size" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hfile.block.cache.size</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Percentage of maximum heap (-Xmx setting) to allocate to block cache used by a StoreFile. Default of 0.4 means allocate 40%. Set to 0 to disable but it’s not recommended; you need at least enough cache to hold the storefile indices.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">0.4</code></p>
</div>
</dd>
</dl>
</div>
<div id="hfile.block.index.cacheonwrite" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hfile.block.index.cacheonwrite</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>This allows to put non-root multi-level index blocks into the block cache at the time the index is being written.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">false</code></p>
</div>
</dd>
</dl>
</div>
<div id="hfile.index.block.max.size" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hfile.index.block.max.size</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>When the size of a leaf-level, intermediate-level, or root-level index block in a multi-level block index grows to this size, the block is written out and a new block is started.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p><code class="notranslate">131072</code></p>
</div>
</dd>
</dl>
</div>
<div id="hbase.bucketcache.ioengine" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.bucketcache.ioengine</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>Where to store the contents of the bucketcache. One of: offheap, file, files or mmap. If a file or files, set it to file(s):PATH_TO_FILE. mmap means the content will be in an mmaped file. Use mmap:PATH_TO_FILE. See <a href="javascript:window.open('https://hbase.apache.org/book.html#offheap.blockcache');" class="bare" target="_blank" rel="noopener noreferrer">http://hbase.apache.org/book.html#offheap.blockcache <i class="fa fa-external-link"></i></a> for more information.</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p>none</p>
</div>
</dd>
</dl>
</div>
<div id="hbase.bucketcache.size" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.bucketcache.size</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>A float that EITHER represents a percentage of total heap memory size to give to the cache (if &lt; 1.0) OR, it is the total capacity in megabytes of BucketCache. Default: 0.0</p>
</div>
<div class="paragraph">
<div class="title">
Default
</div>
<p>none</p>
</div>
</dd>
</dl>
</div>
<div id="hbase.bucketcache.bucket.sizes" class="dlist">
<dl>
<dt class="hdlist1">
<code class="notranslate">hbase.bucketcache.bucket.sizes</code>
</dt>
<dd>
<div class="paragraph">
<div class="title">
Description
</div>
<p>A comma-separated list of sizes for buckets for the bucketcache. Can be multiple sizes. List block sizes in order from smallest to largest. The sizes you use will depend on your data access patterns. Must be a multiple of 256 else you will run into 'java.io.IOException: Invalid HFile block magic' when you go to read from cache. If you specify no values here, then you pick up the default bucketsiz</p>
</div>
</dd>
</dl>
</div>
</div>
</div>
</div>
</div></div>
</div>
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